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![2-1/2" Pump Union Kit — Union Nut, S Tailpiece & O-Ring for Hot Tubs and Spas
Got a leaking pump union? Don't drain your hot tub budget on a service call. This complete 2-1/2" pump union kit gives you everything you need to stop the leak and get your spa back up and running — fast.
Shop and order at Western Tub and Pool
Call us: 1-855-248-0777 | Email: fixmytub@gmail.com
[Shop Our Online Catalogue]
What's Included in This Kit
This kit contains all three components needed for a complete pump union replacement or repair on most standard hot tub and spa installations:
2-1/2" Union Nut — Buttress thread design for a secure, leak-resistant connection
2-1/2" S (Slip) Tailpiece — Fits directly into the pump port for a clean, watertight fit
O-Ring / Gasket — Provides the compression seal between the tailpiece and union nut
No hunting down three separate parts. Everything arrives together, ready to install.
Product Specifications
Specification
Detail
Union Nut Thread Type
2-1/2" Female Buttress Thread (FBT)
Tailpiece Connection Type
2-1/2" Slip (S)
Tailpiece Dimensions
Approx. 3.5" L x 3.5" W x 1.25" D
Material
Durable PVC / ABS plastic
O-Ring Outer Diameter
Approx. 3-7/16" OD
Application
Pump union (jet pump plumbing)
Common Manufacturer
Waterway Plastics
Common Alternate Part Numbers: 415-6000 (union nut), 417-5970 (tailpiece), V40-421S (O-ring), WW4175970, 9175-10A, 610881
Note: This kit is designed for pump unions. If you need a union for a heater connection, a different tailpiece profile may be required. Not sure? Call us — we'll help you confirm the right part.
Compatible Hot Tub Brands and Models
This 2-1/2" pump union configuration is widely used across many popular hot tub and spa brands. Compatible models commonly include those manufactured by or controlled with systems from:
Brands:
Waterway
Balboa Water Group
HydroQuip / Water Pro
Jacuzzi
Sundance Spas
Caldera Spas
Marquis Spas
Master Spas
Cal Spas
Coleman / Maax Spas
Dimension One Spas
Artesian Spas
Dynasty Spas
Vita Spas
Compatible pump types commonly include:
Waterway Hi-Flo, Executive, and EX2 Series
Aqua Flo FMHP and XP2 Series
BWG Vico Dura-Jet and Ultimax Series
LX 48 and 56 Series Pumps
Not sure if this part fits your spa? Check your existing part number, or send us your spa's make, model, and serial number and we'll confirm compatibility for you.
Why This Is a Hard-to-Find Part — and Why We Stock It
Pump unions take a beating. Constant pressure cycles, chemical exposure, and UV degradation cause union nuts to crack and O-rings to harden and fail over time. When that happens, water finds a way out — and a small leak can become a big problem quickly.
The challenge? This part isn't always sitting on the shelf at your local hardware store. It requires the right thread profile (buttress thread, not standard pipe thread), the right slip size, and a matching O-ring. Getting just one of these wrong means the repair won't hold.
At Western Tub and Pool, we stock the parts that are genuinely hard to find — so you don't have to wait weeks or cobble together mismatched components.
How to Install Your New Pump Union
Step 1: Turn off power and drain the pump area
Switch off the spa at the breaker and allow pressure to release before touching any plumbing connections.
Step 2: Unscrew the old union nut
Turn the union nut counterclockwise to disconnect the pump from the plumbing line. If the nut is cracked or seized, a split-nut replacement tool may be required.
Step 3: Remove the old tailpiece and O-ring
Pull the tailpiece free from the pump port. Inspect and discard the old O-ring — never reuse a compressed or damaged O-ring.
Step 4: Install the new tailpiece and O-ring
Insert the new tailpiece into the pump port. Seat the new O-ring into its groove, applying a small amount of silicone lubricant for a better seal.
Step 5: Thread on the union nut and tighten
Hand-tighten the new union nut onto the buttress threads, then snug it with a strap wrench — do not over-torque. Restore power and check for leaks.
Need a hand? Western Tub and Pool offers free home tutorials on hot tub and spa maintenance. We're happy to walk you through the repair — call us at 1-855-248-0777.
Frequently Asked Questions
How do I know if this is the right union for my spa?
The best way to confirm is to check the part number printed or stamped on your existing union nut or tailpiece. Common numbers for this configuration include 415-6000 (nut) and 417-5970 (tailpiece). If your part number isn't visible, send us a photo along with your spa's make, model, and serial number and we'll identify it for you. Email fixmytub@gmail.com or call 1-855-248-0777.
Does this kit include the O-ring?
Yes. This listing includes the union nut, S tailpiece, and O-ring — all three components needed for a complete pump union assembly.
What is a buttress thread, and does it matter?
Yes, it matters. Buttress thread is a specialized thread profile used on spa pump unions — it is not interchangeable with standard NPT (pipe thread) fittings. Using the wrong thread type will result in cross-threading or a failed seal. This kit uses the correct 2-1/2" female buttress thread (FBT) profile.
My union nut is cracked and difficult to access. Can it still be replaced?
If your existing nut is cracked but still attached, a split-nut design may allow you to replace it without cutting the plumbing. We carry those as well — ask us about the right option for your situation.
Can I use this part on a heater union?
No. This tailpiece is designed for pump union connections and uses a small flange suited to pump ports. Heater unions use a different tailpiece profile. If you need a heater union, contact us and we'll point you to the correct part.
Do you offer help identifying parts I can't find elsewhere?
Absolutely. Hard-to-find parts are our specialty. Send us a photo of the part, your spa's serial number, or any part numbers you can find, and our team will track down what you need. Email fixmytub@gmail.com or browse our online catalogue.
Can't Find Your Part?
If you're not sure what you're looking for — or if you've already searched everywhere else — Western Tub and Pool can help. We specialize in hard-to-find hot tub and spa parts and carry a wide range of replacement components for most major brands.
Here's how to reach us:
Phone: 1-855-248-0777
Email: fixmytub@gmail.com
Online: Browse our full parts catalogue
Send us your part number (if known), photos of the part, or your hot tub's make, model, and serial number — and we'll take it from there.
[Shop and Order at Western Tub and Pool]](https://cdn11.bigcommerce.com/s-b7yzllubsu/images/stencil/1280x1280/products/4201/6242/SPA-WW400-5990__79687.1773441000.jpg?c=2 "2-1/2\" Pump Union Kit — Union Nut, S Tailpiece & O-Ring for Hot Tubs and Spas
Got a leaking pump union? Don't drain your hot tub budget on a service call. This complete 2-1/2\" pump union kit gives you everything you need to stop the leak and get your spa back up and running — fast.
Shop and order at Western Tub and Pool
Call us: 1-855-248-0777 | Email: fixmytub@gmail.com
[Shop Our Online Catalogue]
What's Included in This Kit
This kit contains all three components needed for a complete pump union replacement or repair on most standard hot tub and spa installations:
2-1/2\" Union Nut — Buttress thread design for a secure, leak-resistant connection
2-1/2\" S (Slip) Tailpiece — Fits directly into the pump port for a clean, watertight fit
O-Ring / Gasket — Provides the compression seal between the tailpiece and union nut
No hunting down three separate parts. Everything arrives together, ready to install.
Product Specifications
Specification
Detail
Union Nut Thread Type
2-1/2\" Female Buttress Thread (FBT)
Tailpiece Connection Type
2-1/2\" Slip (S)
Tailpiece Dimensions
Approx. 3.5\" L x 3.5\" W x 1.25\" D
Material
Durable PVC / ABS plastic
O-Ring Outer Diameter
Approx. 3-7/16\" OD
Application
Pump union (jet pump plumbing)
Common Manufacturer
Waterway Plastics
Common Alternate Part Numbers: 415-6000 (union nut), 417-5970 (tailpiece), V40-421S (O-ring), WW4175970, 9175-10A, 610881
Note: This kit is designed for pump unions. If you need a union for a heater connection, a different tailpiece profile may be required. Not sure? Call us — we'll help you confirm the right part.
Compatible Hot Tub Brands and Models
This 2-1/2\" pump union configuration is widely used across many popular hot tub and spa brands. Compatible models commonly include those manufactured by or controlled with systems from:
Brands:
Waterway
Balboa Water Group
HydroQuip / Water Pro
Jacuzzi
Sundance Spas
Caldera Spas
Marquis Spas
Master Spas
Cal Spas
Coleman / Maax Spas
Dimension One Spas
Artesian Spas
Dynasty Spas
Vita Spas
Compatible pump types commonly include:
Waterway Hi-Flo, Executive, and EX2 Series
Aqua Flo FMHP and XP2 Series
BWG Vico Dura-Jet and Ultimax Series
LX 48 and 56 Series Pumps
Not sure if this part fits your spa? Check your existing part number, or send us your spa's make, model, and serial number and we'll confirm compatibility for you.
Why This Is a Hard-to-Find Part — and Why We Stock It
Pump unions take a beating. Constant pressure cycles, chemical exposure, and UV degradation cause union nuts to crack and O-rings to harden and fail over time. When that happens, water finds a way out — and a small leak can become a big problem quickly.
The challenge? This part isn't always sitting on the shelf at your local hardware store. It requires the right thread profile (buttress thread, not standard pipe thread), the right slip size, and a matching O-ring. Getting just one of these wrong means the repair won't hold.
At Western Tub and Pool, we stock the parts that are genuinely hard to find — so you don't have to wait weeks or cobble together mismatched components.
How to Install Your New Pump Union
Step 1: Turn off power and drain the pump area
Switch off the spa at the breaker and allow pressure to release before touching any plumbing connections.
Step 2: Unscrew the old union nut
Turn the union nut counterclockwise to disconnect the pump from the plumbing line. If the nut is cracked or seized, a split-nut replacement tool may be required.
Step 3: Remove the old tailpiece and O-ring
Pull the tailpiece free from the pump port. Inspect and discard the old O-ring — never reuse a compressed or damaged O-ring.
Step 4: Install the new tailpiece and O-ring
Insert the new tailpiece into the pump port. Seat the new O-ring into its groove, applying a small amount of silicone lubricant for a better seal.
Step 5: Thread on the union nut and tighten
Hand-tighten the new union nut onto the buttress threads, then snug it with a strap wrench — do not over-torque. Restore power and check for leaks.
Need a hand? Western Tub and Pool offers free home tutorials on hot tub and spa maintenance. We're happy to walk you through the repair — call us at 1-855-248-0777.
Frequently Asked Questions
How do I know if this is the right union for my spa?
The best way to confirm is to check the part number printed or stamped on your existing union nut or tailpiece. Common numbers for this configuration include 415-6000 (nut) and 417-5970 (tailpiece). If your part number isn't visible, send us a photo along with your spa's make, model, and serial number and we'll identify it for you. Email fixmytub@gmail.com or call 1-855-248-0777.
Does this kit include the O-ring?
Yes. This listing includes the union nut, S tailpiece, and O-ring — all three components needed for a complete pump union assembly.
What is a buttress thread, and does it matter?
Yes, it matters. Buttress thread is a specialized thread profile used on spa pump unions — it is not interchangeable with standard NPT (pipe thread) fittings. Using the wrong thread type will result in cross-threading or a failed seal. This kit uses the correct 2-1/2\" female buttress thread (FBT) profile.
My union nut is cracked and difficult to access. Can it still be replaced?
If your existing nut is cracked but still attached, a split-nut design may allow you to replace it without cutting the plumbing. We carry those as well — ask us about the right option for your situation.
Can I use this part on a heater union?
No. This tailpiece is designed for pump union connections and uses a small flange suited to pump ports. Heater unions use a different tailpiece profile. If you need a heater union, contact us and we'll point you to the correct part.
Do you offer help identifying parts I can't find elsewhere?
Absolutely. Hard-to-find parts are our specialty. Send us a photo of the part, your spa's serial number, or any part numbers you can find, and our team will track down what you need. Email fixmytub@gmail.com or browse our online catalogue.
Can't Find Your Part?
If you're not sure what you're looking for — or if you've already searched everywhere else — Western Tub and Pool can help. We specialize in hard-to-find hot tub and spa parts and carry a wide range of replacement components for most major brands.
Here's how to reach us:
Phone: 1-855-248-0777
Email: fixmytub@gmail.com
Online: Browse our full parts catalogue
Send us your part number (if known), photos of the part, or your hot tub's make, model, and serial number — and we'll take it from there.
[Shop and Order at Western Tub and Pool]")
![2-1/2" Pump Union Kit — Union Nut, S Tailpiece & O-Ring for Hot Tubs and Spas
Got a leaking pump union? Don't drain your hot tub budget on a service call. This complete 2-1/2" pump union kit gives you everything you need to stop the leak and get your spa back up and running — fast.
Shop and order at Western Tub and Pool
Call us: 1-855-248-0777 | Email: fixmytub@gmail.com
[Shop Our Online Catalogue]
What's Included in This Kit
This kit contains all three components needed for a complete pump union replacement or repair on most standard hot tub and spa installations:
2-1/2" Union Nut — Buttress thread design for a secure, leak-resistant connection
2-1/2" S (Slip) Tailpiece — Fits directly into the pump port for a clean, watertight fit
O-Ring / Gasket — Provides the compression seal between the tailpiece and union nut
No hunting down three separate parts. Everything arrives together, ready to install.
Product Specifications
Specification
Detail
Union Nut Thread Type
2-1/2" Female Buttress Thread (FBT)
Tailpiece Connection Type
2-1/2" Slip (S)
Tailpiece Dimensions
Approx. 3.5" L x 3.5" W x 1.25" D
Material
Durable PVC / ABS plastic
O-Ring Outer Diameter
Approx. 3-7/16" OD
Application
Pump union (jet pump plumbing)
Common Manufacturer
Waterway Plastics
Common Alternate Part Numbers: 415-6000 (union nut), 417-5970 (tailpiece), V40-421S (O-ring), WW4175970, 9175-10A, 610881
Note: This kit is designed for pump unions. If you need a union for a heater connection, a different tailpiece profile may be required. Not sure? Call us — we'll help you confirm the right part.
Compatible Hot Tub Brands and Models
This 2-1/2" pump union configuration is widely used across many popular hot tub and spa brands. Compatible models commonly include those manufactured by or controlled with systems from:
Brands:
Waterway
Balboa Water Group
HydroQuip / Water Pro
Jacuzzi
Sundance Spas
Caldera Spas
Marquis Spas
Master Spas
Cal Spas
Coleman / Maax Spas
Dimension One Spas
Artesian Spas
Dynasty Spas
Vita Spas
Compatible pump types commonly include:
Waterway Hi-Flo, Executive, and EX2 Series
Aqua Flo FMHP and XP2 Series
BWG Vico Dura-Jet and Ultimax Series
LX 48 and 56 Series Pumps
Not sure if this part fits your spa? Check your existing part number, or send us your spa's make, model, and serial number and we'll confirm compatibility for you.
Why This Is a Hard-to-Find Part — and Why We Stock It
Pump unions take a beating. Constant pressure cycles, chemical exposure, and UV degradation cause union nuts to crack and O-rings to harden and fail over time. When that happens, water finds a way out — and a small leak can become a big problem quickly.
The challenge? This part isn't always sitting on the shelf at your local hardware store. It requires the right thread profile (buttress thread, not standard pipe thread), the right slip size, and a matching O-ring. Getting just one of these wrong means the repair won't hold.
At Western Tub and Pool, we stock the parts that are genuinely hard to find — so you don't have to wait weeks or cobble together mismatched components.
How to Install Your New Pump Union
Step 1: Turn off power and drain the pump area
Switch off the spa at the breaker and allow pressure to release before touching any plumbing connections.
Step 2: Unscrew the old union nut
Turn the union nut counterclockwise to disconnect the pump from the plumbing line. If the nut is cracked or seized, a split-nut replacement tool may be required.
Step 3: Remove the old tailpiece and O-ring
Pull the tailpiece free from the pump port. Inspect and discard the old O-ring — never reuse a compressed or damaged O-ring.
Step 4: Install the new tailpiece and O-ring
Insert the new tailpiece into the pump port. Seat the new O-ring into its groove, applying a small amount of silicone lubricant for a better seal.
Step 5: Thread on the union nut and tighten
Hand-tighten the new union nut onto the buttress threads, then snug it with a strap wrench — do not over-torque. Restore power and check for leaks.
Need a hand? Western Tub and Pool offers free home tutorials on hot tub and spa maintenance. We're happy to walk you through the repair — call us at 1-855-248-0777.
Frequently Asked Questions
How do I know if this is the right union for my spa?
The best way to confirm is to check the part number printed or stamped on your existing union nut or tailpiece. Common numbers for this configuration include 415-6000 (nut) and 417-5970 (tailpiece). If your part number isn't visible, send us a photo along with your spa's make, model, and serial number and we'll identify it for you. Email fixmytub@gmail.com or call 1-855-248-0777.
Does this kit include the O-ring?
Yes. This listing includes the union nut, S tailpiece, and O-ring — all three components needed for a complete pump union assembly.
What is a buttress thread, and does it matter?
Yes, it matters. Buttress thread is a specialized thread profile used on spa pump unions — it is not interchangeable with standard NPT (pipe thread) fittings. Using the wrong thread type will result in cross-threading or a failed seal. This kit uses the correct 2-1/2" female buttress thread (FBT) profile.
My union nut is cracked and difficult to access. Can it still be replaced?
If your existing nut is cracked but still attached, a split-nut design may allow you to replace it without cutting the plumbing. We carry those as well — ask us about the right option for your situation.
Can I use this part on a heater union?
No. This tailpiece is designed for pump union connections and uses a small flange suited to pump ports. Heater unions use a different tailpiece profile. If you need a heater union, contact us and we'll point you to the correct part.
Do you offer help identifying parts I can't find elsewhere?
Absolutely. Hard-to-find parts are our specialty. Send us a photo of the part, your spa's serial number, or any part numbers you can find, and our team will track down what you need. Email fixmytub@gmail.com or browse our online catalogue.
Can't Find Your Part?
If you're not sure what you're looking for — or if you've already searched everywhere else — Western Tub and Pool can help. We specialize in hard-to-find hot tub and spa parts and carry a wide range of replacement components for most major brands.
Here's how to reach us:
Phone: 1-855-248-0777
Email: fixmytub@gmail.com
Online: Browse our full parts catalogue
Send us your part number (if known), photos of the part, or your hot tub's make, model, and serial number — and we'll take it from there.
[Shop and Order at Western Tub and Pool]](https://cdn11.bigcommerce.com/s-b7yzllubsu/images/stencil/1280x1280/products/4201/6243/0000660_waterway-2-12-union-nut-with-2-12-s-tailpiece-and-o-ring-600x600__89006.1773441032.jpg?c=2 "2-1/2\" Pump Union Kit — Union Nut, S Tailpiece & O-Ring for Hot Tubs and Spas
Got a leaking pump union? Don't drain your hot tub budget on a service call. This complete 2-1/2\" pump union kit gives you everything you need to stop the leak and get your spa back up and running — fast.
Shop and order at Western Tub and Pool
Call us: 1-855-248-0777 | Email: fixmytub@gmail.com
[Shop Our Online Catalogue]
What's Included in This Kit
This kit contains all three components needed for a complete pump union replacement or repair on most standard hot tub and spa installations:
2-1/2\" Union Nut — Buttress thread design for a secure, leak-resistant connection
2-1/2\" S (Slip) Tailpiece — Fits directly into the pump port for a clean, watertight fit
O-Ring / Gasket — Provides the compression seal between the tailpiece and union nut
No hunting down three separate parts. Everything arrives together, ready to install.
Product Specifications
Specification
Detail
Union Nut Thread Type
2-1/2\" Female Buttress Thread (FBT)
Tailpiece Connection Type
2-1/2\" Slip (S)
Tailpiece Dimensions
Approx. 3.5\" L x 3.5\" W x 1.25\" D
Material
Durable PVC / ABS plastic
O-Ring Outer Diameter
Approx. 3-7/16\" OD
Application
Pump union (jet pump plumbing)
Common Manufacturer
Waterway Plastics
Common Alternate Part Numbers: 415-6000 (union nut), 417-5970 (tailpiece), V40-421S (O-ring), WW4175970, 9175-10A, 610881
Note: This kit is designed for pump unions. If you need a union for a heater connection, a different tailpiece profile may be required. Not sure? Call us — we'll help you confirm the right part.
Compatible Hot Tub Brands and Models
This 2-1/2\" pump union configuration is widely used across many popular hot tub and spa brands. Compatible models commonly include those manufactured by or controlled with systems from:
Brands:
Waterway
Balboa Water Group
HydroQuip / Water Pro
Jacuzzi
Sundance Spas
Caldera Spas
Marquis Spas
Master Spas
Cal Spas
Coleman / Maax Spas
Dimension One Spas
Artesian Spas
Dynasty Spas
Vita Spas
Compatible pump types commonly include:
Waterway Hi-Flo, Executive, and EX2 Series
Aqua Flo FMHP and XP2 Series
BWG Vico Dura-Jet and Ultimax Series
LX 48 and 56 Series Pumps
Not sure if this part fits your spa? Check your existing part number, or send us your spa's make, model, and serial number and we'll confirm compatibility for you.
Why This Is a Hard-to-Find Part — and Why We Stock It
Pump unions take a beating. Constant pressure cycles, chemical exposure, and UV degradation cause union nuts to crack and O-rings to harden and fail over time. When that happens, water finds a way out — and a small leak can become a big problem quickly.
The challenge? This part isn't always sitting on the shelf at your local hardware store. It requires the right thread profile (buttress thread, not standard pipe thread), the right slip size, and a matching O-ring. Getting just one of these wrong means the repair won't hold.
At Western Tub and Pool, we stock the parts that are genuinely hard to find — so you don't have to wait weeks or cobble together mismatched components.
How to Install Your New Pump Union
Step 1: Turn off power and drain the pump area
Switch off the spa at the breaker and allow pressure to release before touching any plumbing connections.
Step 2: Unscrew the old union nut
Turn the union nut counterclockwise to disconnect the pump from the plumbing line. If the nut is cracked or seized, a split-nut replacement tool may be required.
Step 3: Remove the old tailpiece and O-ring
Pull the tailpiece free from the pump port. Inspect and discard the old O-ring — never reuse a compressed or damaged O-ring.
Step 4: Install the new tailpiece and O-ring
Insert the new tailpiece into the pump port. Seat the new O-ring into its groove, applying a small amount of silicone lubricant for a better seal.
Step 5: Thread on the union nut and tighten
Hand-tighten the new union nut onto the buttress threads, then snug it with a strap wrench — do not over-torque. Restore power and check for leaks.
Need a hand? Western Tub and Pool offers free home tutorials on hot tub and spa maintenance. We're happy to walk you through the repair — call us at 1-855-248-0777.
Frequently Asked Questions
How do I know if this is the right union for my spa?
The best way to confirm is to check the part number printed or stamped on your existing union nut or tailpiece. Common numbers for this configuration include 415-6000 (nut) and 417-5970 (tailpiece). If your part number isn't visible, send us a photo along with your spa's make, model, and serial number and we'll identify it for you. Email fixmytub@gmail.com or call 1-855-248-0777.
Does this kit include the O-ring?
Yes. This listing includes the union nut, S tailpiece, and O-ring — all three components needed for a complete pump union assembly.
What is a buttress thread, and does it matter?
Yes, it matters. Buttress thread is a specialized thread profile used on spa pump unions — it is not interchangeable with standard NPT (pipe thread) fittings. Using the wrong thread type will result in cross-threading or a failed seal. This kit uses the correct 2-1/2\" female buttress thread (FBT) profile.
My union nut is cracked and difficult to access. Can it still be replaced?
If your existing nut is cracked but still attached, a split-nut design may allow you to replace it without cutting the plumbing. We carry those as well — ask us about the right option for your situation.
Can I use this part on a heater union?
No. This tailpiece is designed for pump union connections and uses a small flange suited to pump ports. Heater unions use a different tailpiece profile. If you need a heater union, contact us and we'll point you to the correct part.
Do you offer help identifying parts I can't find elsewhere?
Absolutely. Hard-to-find parts are our specialty. Send us a photo of the part, your spa's serial number, or any part numbers you can find, and our team will track down what you need. Email fixmytub@gmail.com or browse our online catalogue.
Can't Find Your Part?
If you're not sure what you're looking for — or if you've already searched everywhere else — Western Tub and Pool can help. We specialize in hard-to-find hot tub and spa parts and carry a wide range of replacement components for most major brands.
Here's how to reach us:
Phone: 1-855-248-0777
Email: fixmytub@gmail.com
Online: Browse our full parts catalogue
Send us your part number (if known), photos of the part, or your hot tub's make, model, and serial number — and we'll take it from there.
[Shop and Order at Western Tub and Pool]")
![2-1/2" Pump Union Kit — Union Nut, S Tailpiece & O-Ring for Hot Tubs and Spas
Got a leaking pump union? Don't drain your hot tub budget on a service call. This complete 2-1/2" pump union kit gives you everything you need to stop the leak and get your spa back up and running — fast.
Shop and order at Western Tub and Pool
Call us: 1-855-248-0777 | Email: fixmytub@gmail.com
[Shop Our Online Catalogue]
What's Included in This Kit
This kit contains all three components needed for a complete pump union replacement or repair on most standard hot tub and spa installations:
2-1/2" Union Nut — Buttress thread design for a secure, leak-resistant connection
2-1/2" S (Slip) Tailpiece — Fits directly into the pump port for a clean, watertight fit
O-Ring / Gasket — Provides the compression seal between the tailpiece and union nut
No hunting down three separate parts. Everything arrives together, ready to install.
Product Specifications
Specification
Detail
Union Nut Thread Type
2-1/2" Female Buttress Thread (FBT)
Tailpiece Connection Type
2-1/2" Slip (S)
Tailpiece Dimensions
Approx. 3.5" L x 3.5" W x 1.25" D
Material
Durable PVC / ABS plastic
O-Ring Outer Diameter
Approx. 3-7/16" OD
Application
Pump union (jet pump plumbing)
Common Manufacturer
Waterway Plastics
Common Alternate Part Numbers: 415-6000 (union nut), 417-5970 (tailpiece), V40-421S (O-ring), WW4175970, 9175-10A, 610881
Note: This kit is designed for pump unions. If you need a union for a heater connection, a different tailpiece profile may be required. Not sure? Call us — we'll help you confirm the right part.
Compatible Hot Tub Brands and Models
This 2-1/2" pump union configuration is widely used across many popular hot tub and spa brands. Compatible models commonly include those manufactured by or controlled with systems from:
Brands:
Waterway
Balboa Water Group
HydroQuip / Water Pro
Jacuzzi
Sundance Spas
Caldera Spas
Marquis Spas
Master Spas
Cal Spas
Coleman / Maax Spas
Dimension One Spas
Artesian Spas
Dynasty Spas
Vita Spas
Compatible pump types commonly include:
Waterway Hi-Flo, Executive, and EX2 Series
Aqua Flo FMHP and XP2 Series
BWG Vico Dura-Jet and Ultimax Series
LX 48 and 56 Series Pumps
Not sure if this part fits your spa? Check your existing part number, or send us your spa's make, model, and serial number and we'll confirm compatibility for you.
Why This Is a Hard-to-Find Part — and Why We Stock It
Pump unions take a beating. Constant pressure cycles, chemical exposure, and UV degradation cause union nuts to crack and O-rings to harden and fail over time. When that happens, water finds a way out — and a small leak can become a big problem quickly.
The challenge? This part isn't always sitting on the shelf at your local hardware store. It requires the right thread profile (buttress thread, not standard pipe thread), the right slip size, and a matching O-ring. Getting just one of these wrong means the repair won't hold.
At Western Tub and Pool, we stock the parts that are genuinely hard to find — so you don't have to wait weeks or cobble together mismatched components.
How to Install Your New Pump Union
Step 1: Turn off power and drain the pump area
Switch off the spa at the breaker and allow pressure to release before touching any plumbing connections.
Step 2: Unscrew the old union nut
Turn the union nut counterclockwise to disconnect the pump from the plumbing line. If the nut is cracked or seized, a split-nut replacement tool may be required.
Step 3: Remove the old tailpiece and O-ring
Pull the tailpiece free from the pump port. Inspect and discard the old O-ring — never reuse a compressed or damaged O-ring.
Step 4: Install the new tailpiece and O-ring
Insert the new tailpiece into the pump port. Seat the new O-ring into its groove, applying a small amount of silicone lubricant for a better seal.
Step 5: Thread on the union nut and tighten
Hand-tighten the new union nut onto the buttress threads, then snug it with a strap wrench — do not over-torque. Restore power and check for leaks.
Need a hand? Western Tub and Pool offers free home tutorials on hot tub and spa maintenance. We're happy to walk you through the repair — call us at 1-855-248-0777.
Frequently Asked Questions
How do I know if this is the right union for my spa?
The best way to confirm is to check the part number printed or stamped on your existing union nut or tailpiece. Common numbers for this configuration include 415-6000 (nut) and 417-5970 (tailpiece). If your part number isn't visible, send us a photo along with your spa's make, model, and serial number and we'll identify it for you. Email fixmytub@gmail.com or call 1-855-248-0777.
Does this kit include the O-ring?
Yes. This listing includes the union nut, S tailpiece, and O-ring — all three components needed for a complete pump union assembly.
What is a buttress thread, and does it matter?
Yes, it matters. Buttress thread is a specialized thread profile used on spa pump unions — it is not interchangeable with standard NPT (pipe thread) fittings. Using the wrong thread type will result in cross-threading or a failed seal. This kit uses the correct 2-1/2" female buttress thread (FBT) profile.
My union nut is cracked and difficult to access. Can it still be replaced?
If your existing nut is cracked but still attached, a split-nut design may allow you to replace it without cutting the plumbing. We carry those as well — ask us about the right option for your situation.
Can I use this part on a heater union?
No. This tailpiece is designed for pump union connections and uses a small flange suited to pump ports. Heater unions use a different tailpiece profile. If you need a heater union, contact us and we'll point you to the correct part.
Do you offer help identifying parts I can't find elsewhere?
Absolutely. Hard-to-find parts are our specialty. Send us a photo of the part, your spa's serial number, or any part numbers you can find, and our team will track down what you need. Email fixmytub@gmail.com or browse our online catalogue.
Can't Find Your Part?
If you're not sure what you're looking for — or if you've already searched everywhere else — Western Tub and Pool can help. We specialize in hard-to-find hot tub and spa parts and carry a wide range of replacement components for most major brands.
Here's how to reach us:
Phone: 1-855-248-0777
Email: fixmytub@gmail.com
Online: Browse our full parts catalogue
Send us your part number (if known), photos of the part, or your hot tub's make, model, and serial number — and we'll take it from there.
[Shop and Order at Western Tub and Pool]](https://cdn11.bigcommerce.com/s-b7yzllubsu/images/stencil/100x100/products/4201/6242/SPA-WW400-5990__79687.1773441000.jpg?c=2 "2-1/2\" Pump Union Kit — Union Nut, S Tailpiece & O-Ring for Hot Tubs and Spas
Got a leaking pump union? Don't drain your hot tub budget on a service call. This complete 2-1/2\" pump union kit gives you everything you need to stop the leak and get your spa back up and running — fast.
Shop and order at Western Tub and Pool
Call us: 1-855-248-0777 | Email: fixmytub@gmail.com
[Shop Our Online Catalogue]
What's Included in This Kit
This kit contains all three components needed for a complete pump union replacement or repair on most standard hot tub and spa installations:
2-1/2\" Union Nut — Buttress thread design for a secure, leak-resistant connection
2-1/2\" S (Slip) Tailpiece — Fits directly into the pump port for a clean, watertight fit
O-Ring / Gasket — Provides the compression seal between the tailpiece and union nut
No hunting down three separate parts. Everything arrives together, ready to install.
Product Specifications
Specification
Detail
Union Nut Thread Type
2-1/2\" Female Buttress Thread (FBT)
Tailpiece Connection Type
2-1/2\" Slip (S)
Tailpiece Dimensions
Approx. 3.5\" L x 3.5\" W x 1.25\" D
Material
Durable PVC / ABS plastic
O-Ring Outer Diameter
Approx. 3-7/16\" OD
Application
Pump union (jet pump plumbing)
Common Manufacturer
Waterway Plastics
Common Alternate Part Numbers: 415-6000 (union nut), 417-5970 (tailpiece), V40-421S (O-ring), WW4175970, 9175-10A, 610881
Note: This kit is designed for pump unions. If you need a union for a heater connection, a different tailpiece profile may be required. Not sure? Call us — we'll help you confirm the right part.
Compatible Hot Tub Brands and Models
This 2-1/2\" pump union configuration is widely used across many popular hot tub and spa brands. Compatible models commonly include those manufactured by or controlled with systems from:
Brands:
Waterway
Balboa Water Group
HydroQuip / Water Pro
Jacuzzi
Sundance Spas
Caldera Spas
Marquis Spas
Master Spas
Cal Spas
Coleman / Maax Spas
Dimension One Spas
Artesian Spas
Dynasty Spas
Vita Spas
Compatible pump types commonly include:
Waterway Hi-Flo, Executive, and EX2 Series
Aqua Flo FMHP and XP2 Series
BWG Vico Dura-Jet and Ultimax Series
LX 48 and 56 Series Pumps
Not sure if this part fits your spa? Check your existing part number, or send us your spa's make, model, and serial number and we'll confirm compatibility for you.
Why This Is a Hard-to-Find Part — and Why We Stock It
Pump unions take a beating. Constant pressure cycles, chemical exposure, and UV degradation cause union nuts to crack and O-rings to harden and fail over time. When that happens, water finds a way out — and a small leak can become a big problem quickly.
The challenge? This part isn't always sitting on the shelf at your local hardware store. It requires the right thread profile (buttress thread, not standard pipe thread), the right slip size, and a matching O-ring. Getting just one of these wrong means the repair won't hold.
At Western Tub and Pool, we stock the parts that are genuinely hard to find — so you don't have to wait weeks or cobble together mismatched components.
How to Install Your New Pump Union
Step 1: Turn off power and drain the pump area
Switch off the spa at the breaker and allow pressure to release before touching any plumbing connections.
Step 2: Unscrew the old union nut
Turn the union nut counterclockwise to disconnect the pump from the plumbing line. If the nut is cracked or seized, a split-nut replacement tool may be required.
Step 3: Remove the old tailpiece and O-ring
Pull the tailpiece free from the pump port. Inspect and discard the old O-ring — never reuse a compressed or damaged O-ring.
Step 4: Install the new tailpiece and O-ring
Insert the new tailpiece into the pump port. Seat the new O-ring into its groove, applying a small amount of silicone lubricant for a better seal.
Step 5: Thread on the union nut and tighten
Hand-tighten the new union nut onto the buttress threads, then snug it with a strap wrench — do not over-torque. Restore power and check for leaks.
Need a hand? Western Tub and Pool offers free home tutorials on hot tub and spa maintenance. We're happy to walk you through the repair — call us at 1-855-248-0777.
Frequently Asked Questions
How do I know if this is the right union for my spa?
The best way to confirm is to check the part number printed or stamped on your existing union nut or tailpiece. Common numbers for this configuration include 415-6000 (nut) and 417-5970 (tailpiece). If your part number isn't visible, send us a photo along with your spa's make, model, and serial number and we'll identify it for you. Email fixmytub@gmail.com or call 1-855-248-0777.
Does this kit include the O-ring?
Yes. This listing includes the union nut, S tailpiece, and O-ring — all three components needed for a complete pump union assembly.
What is a buttress thread, and does it matter?
Yes, it matters. Buttress thread is a specialized thread profile used on spa pump unions — it is not interchangeable with standard NPT (pipe thread) fittings. Using the wrong thread type will result in cross-threading or a failed seal. This kit uses the correct 2-1/2\" female buttress thread (FBT) profile.
My union nut is cracked and difficult to access. Can it still be replaced?
If your existing nut is cracked but still attached, a split-nut design may allow you to replace it without cutting the plumbing. We carry those as well — ask us about the right option for your situation.
Can I use this part on a heater union?
No. This tailpiece is designed for pump union connections and uses a small flange suited to pump ports. Heater unions use a different tailpiece profile. If you need a heater union, contact us and we'll point you to the correct part.
Do you offer help identifying parts I can't find elsewhere?
Absolutely. Hard-to-find parts are our specialty. Send us a photo of the part, your spa's serial number, or any part numbers you can find, and our team will track down what you need. Email fixmytub@gmail.com or browse our online catalogue.
Can't Find Your Part?
If you're not sure what you're looking for — or if you've already searched everywhere else — Western Tub and Pool can help. We specialize in hard-to-find hot tub and spa parts and carry a wide range of replacement components for most major brands.
Here's how to reach us:
Phone: 1-855-248-0777
Email: fixmytub@gmail.com
Online: Browse our full parts catalogue
Send us your part number (if known), photos of the part, or your hot tub's make, model, and serial number — and we'll take it from there.
[Shop and Order at Western Tub and Pool]")
![2-1/2" Pump Union Kit — Union Nut, S Tailpiece & O-Ring for Hot Tubs and Spas
Got a leaking pump union? Don't drain your hot tub budget on a service call. This complete 2-1/2" pump union kit gives you everything you need to stop the leak and get your spa back up and running — fast.
Shop and order at Western Tub and Pool
Call us: 1-855-248-0777 | Email: fixmytub@gmail.com
[Shop Our Online Catalogue]
What's Included in This Kit
This kit contains all three components needed for a complete pump union replacement or repair on most standard hot tub and spa installations:
2-1/2" Union Nut — Buttress thread design for a secure, leak-resistant connection
2-1/2" S (Slip) Tailpiece — Fits directly into the pump port for a clean, watertight fit
O-Ring / Gasket — Provides the compression seal between the tailpiece and union nut
No hunting down three separate parts. Everything arrives together, ready to install.
Product Specifications
Specification
Detail
Union Nut Thread Type
2-1/2" Female Buttress Thread (FBT)
Tailpiece Connection Type
2-1/2" Slip (S)
Tailpiece Dimensions
Approx. 3.5" L x 3.5" W x 1.25" D
Material
Durable PVC / ABS plastic
O-Ring Outer Diameter
Approx. 3-7/16" OD
Application
Pump union (jet pump plumbing)
Common Manufacturer
Waterway Plastics
Common Alternate Part Numbers: 415-6000 (union nut), 417-5970 (tailpiece), V40-421S (O-ring), WW4175970, 9175-10A, 610881
Note: This kit is designed for pump unions. If you need a union for a heater connection, a different tailpiece profile may be required. Not sure? Call us — we'll help you confirm the right part.
Compatible Hot Tub Brands and Models
This 2-1/2" pump union configuration is widely used across many popular hot tub and spa brands. Compatible models commonly include those manufactured by or controlled with systems from:
Brands:
Waterway
Balboa Water Group
HydroQuip / Water Pro
Jacuzzi
Sundance Spas
Caldera Spas
Marquis Spas
Master Spas
Cal Spas
Coleman / Maax Spas
Dimension One Spas
Artesian Spas
Dynasty Spas
Vita Spas
Compatible pump types commonly include:
Waterway Hi-Flo, Executive, and EX2 Series
Aqua Flo FMHP and XP2 Series
BWG Vico Dura-Jet and Ultimax Series
LX 48 and 56 Series Pumps
Not sure if this part fits your spa? Check your existing part number, or send us your spa's make, model, and serial number and we'll confirm compatibility for you.
Why This Is a Hard-to-Find Part — and Why We Stock It
Pump unions take a beating. Constant pressure cycles, chemical exposure, and UV degradation cause union nuts to crack and O-rings to harden and fail over time. When that happens, water finds a way out — and a small leak can become a big problem quickly.
The challenge? This part isn't always sitting on the shelf at your local hardware store. It requires the right thread profile (buttress thread, not standard pipe thread), the right slip size, and a matching O-ring. Getting just one of these wrong means the repair won't hold.
At Western Tub and Pool, we stock the parts that are genuinely hard to find — so you don't have to wait weeks or cobble together mismatched components.
How to Install Your New Pump Union
Step 1: Turn off power and drain the pump area
Switch off the spa at the breaker and allow pressure to release before touching any plumbing connections.
Step 2: Unscrew the old union nut
Turn the union nut counterclockwise to disconnect the pump from the plumbing line. If the nut is cracked or seized, a split-nut replacement tool may be required.
Step 3: Remove the old tailpiece and O-ring
Pull the tailpiece free from the pump port. Inspect and discard the old O-ring — never reuse a compressed or damaged O-ring.
Step 4: Install the new tailpiece and O-ring
Insert the new tailpiece into the pump port. Seat the new O-ring into its groove, applying a small amount of silicone lubricant for a better seal.
Step 5: Thread on the union nut and tighten
Hand-tighten the new union nut onto the buttress threads, then snug it with a strap wrench — do not over-torque. Restore power and check for leaks.
Need a hand? Western Tub and Pool offers free home tutorials on hot tub and spa maintenance. We're happy to walk you through the repair — call us at 1-855-248-0777.
Frequently Asked Questions
How do I know if this is the right union for my spa?
The best way to confirm is to check the part number printed or stamped on your existing union nut or tailpiece. Common numbers for this configuration include 415-6000 (nut) and 417-5970 (tailpiece). If your part number isn't visible, send us a photo along with your spa's make, model, and serial number and we'll identify it for you. Email fixmytub@gmail.com or call 1-855-248-0777.
Does this kit include the O-ring?
Yes. This listing includes the union nut, S tailpiece, and O-ring — all three components needed for a complete pump union assembly.
What is a buttress thread, and does it matter?
Yes, it matters. Buttress thread is a specialized thread profile used on spa pump unions — it is not interchangeable with standard NPT (pipe thread) fittings. Using the wrong thread type will result in cross-threading or a failed seal. This kit uses the correct 2-1/2" female buttress thread (FBT) profile.
My union nut is cracked and difficult to access. Can it still be replaced?
If your existing nut is cracked but still attached, a split-nut design may allow you to replace it without cutting the plumbing. We carry those as well — ask us about the right option for your situation.
Can I use this part on a heater union?
No. This tailpiece is designed for pump union connections and uses a small flange suited to pump ports. Heater unions use a different tailpiece profile. If you need a heater union, contact us and we'll point you to the correct part.
Do you offer help identifying parts I can't find elsewhere?
Absolutely. Hard-to-find parts are our specialty. Send us a photo of the part, your spa's serial number, or any part numbers you can find, and our team will track down what you need. Email fixmytub@gmail.com or browse our online catalogue.
Can't Find Your Part?
If you're not sure what you're looking for — or if you've already searched everywhere else — Western Tub and Pool can help. We specialize in hard-to-find hot tub and spa parts and carry a wide range of replacement components for most major brands.
Here's how to reach us:
Phone: 1-855-248-0777
Email: fixmytub@gmail.com
Online: Browse our full parts catalogue
Send us your part number (if known), photos of the part, or your hot tub's make, model, and serial number — and we'll take it from there.
[Shop and Order at Western Tub and Pool]](https://cdn11.bigcommerce.com/s-b7yzllubsu/images/stencil/100x100/products/4201/6243/0000660_waterway-2-12-union-nut-with-2-12-s-tailpiece-and-o-ring-600x600__89006.1773441032.jpg?c=2 "2-1/2\" Pump Union Kit — Union Nut, S Tailpiece & O-Ring for Hot Tubs and Spas
Got a leaking pump union? Don't drain your hot tub budget on a service call. This complete 2-1/2\" pump union kit gives you everything you need to stop the leak and get your spa back up and running — fast.
Shop and order at Western Tub and Pool
Call us: 1-855-248-0777 | Email: fixmytub@gmail.com
[Shop Our Online Catalogue]
What's Included in This Kit
This kit contains all three components needed for a complete pump union replacement or repair on most standard hot tub and spa installations:
2-1/2\" Union Nut — Buttress thread design for a secure, leak-resistant connection
2-1/2\" S (Slip) Tailpiece — Fits directly into the pump port for a clean, watertight fit
O-Ring / Gasket — Provides the compression seal between the tailpiece and union nut
No hunting down three separate parts. Everything arrives together, ready to install.
Product Specifications
Specification
Detail
Union Nut Thread Type
2-1/2\" Female Buttress Thread (FBT)
Tailpiece Connection Type
2-1/2\" Slip (S)
Tailpiece Dimensions
Approx. 3.5\" L x 3.5\" W x 1.25\" D
Material
Durable PVC / ABS plastic
O-Ring Outer Diameter
Approx. 3-7/16\" OD
Application
Pump union (jet pump plumbing)
Common Manufacturer
Waterway Plastics
Common Alternate Part Numbers: 415-6000 (union nut), 417-5970 (tailpiece), V40-421S (O-ring), WW4175970, 9175-10A, 610881
Note: This kit is designed for pump unions. If you need a union for a heater connection, a different tailpiece profile may be required. Not sure? Call us — we'll help you confirm the right part.
Compatible Hot Tub Brands and Models
This 2-1/2\" pump union configuration is widely used across many popular hot tub and spa brands. Compatible models commonly include those manufactured by or controlled with systems from:
Brands:
Waterway
Balboa Water Group
HydroQuip / Water Pro
Jacuzzi
Sundance Spas
Caldera Spas
Marquis Spas
Master Spas
Cal Spas
Coleman / Maax Spas
Dimension One Spas
Artesian Spas
Dynasty Spas
Vita Spas
Compatible pump types commonly include:
Waterway Hi-Flo, Executive, and EX2 Series
Aqua Flo FMHP and XP2 Series
BWG Vico Dura-Jet and Ultimax Series
LX 48 and 56 Series Pumps
Not sure if this part fits your spa? Check your existing part number, or send us your spa's make, model, and serial number and we'll confirm compatibility for you.
Why This Is a Hard-to-Find Part — and Why We Stock It
Pump unions take a beating. Constant pressure cycles, chemical exposure, and UV degradation cause union nuts to crack and O-rings to harden and fail over time. When that happens, water finds a way out — and a small leak can become a big problem quickly.
The challenge? This part isn't always sitting on the shelf at your local hardware store. It requires the right thread profile (buttress thread, not standard pipe thread), the right slip size, and a matching O-ring. Getting just one of these wrong means the repair won't hold.
At Western Tub and Pool, we stock the parts that are genuinely hard to find — so you don't have to wait weeks or cobble together mismatched components.
How to Install Your New Pump Union
Step 1: Turn off power and drain the pump area
Switch off the spa at the breaker and allow pressure to release before touching any plumbing connections.
Step 2: Unscrew the old union nut
Turn the union nut counterclockwise to disconnect the pump from the plumbing line. If the nut is cracked or seized, a split-nut replacement tool may be required.
Step 3: Remove the old tailpiece and O-ring
Pull the tailpiece free from the pump port. Inspect and discard the old O-ring — never reuse a compressed or damaged O-ring.
Step 4: Install the new tailpiece and O-ring
Insert the new tailpiece into the pump port. Seat the new O-ring into its groove, applying a small amount of silicone lubricant for a better seal.
Step 5: Thread on the union nut and tighten
Hand-tighten the new union nut onto the buttress threads, then snug it with a strap wrench — do not over-torque. Restore power and check for leaks.
Need a hand? Western Tub and Pool offers free home tutorials on hot tub and spa maintenance. We're happy to walk you through the repair — call us at 1-855-248-0777.
Frequently Asked Questions
How do I know if this is the right union for my spa?
The best way to confirm is to check the part number printed or stamped on your existing union nut or tailpiece. Common numbers for this configuration include 415-6000 (nut) and 417-5970 (tailpiece). If your part number isn't visible, send us a photo along with your spa's make, model, and serial number and we'll identify it for you. Email fixmytub@gmail.com or call 1-855-248-0777.
Does this kit include the O-ring?
Yes. This listing includes the union nut, S tailpiece, and O-ring — all three components needed for a complete pump union assembly.
What is a buttress thread, and does it matter?
Yes, it matters. Buttress thread is a specialized thread profile used on spa pump unions — it is not interchangeable with standard NPT (pipe thread) fittings. Using the wrong thread type will result in cross-threading or a failed seal. This kit uses the correct 2-1/2\" female buttress thread (FBT) profile.
My union nut is cracked and difficult to access. Can it still be replaced?
If your existing nut is cracked but still attached, a split-nut design may allow you to replace it without cutting the plumbing. We carry those as well — ask us about the right option for your situation.
Can I use this part on a heater union?
No. This tailpiece is designed for pump union connections and uses a small flange suited to pump ports. Heater unions use a different tailpiece profile. If you need a heater union, contact us and we'll point you to the correct part.
Do you offer help identifying parts I can't find elsewhere?
Absolutely. Hard-to-find parts are our specialty. Send us a photo of the part, your spa's serial number, or any part numbers you can find, and our team will track down what you need. Email fixmytub@gmail.com or browse our online catalogue.
Can't Find Your Part?
If you're not sure what you're looking for — or if you've already searched everywhere else — Western Tub and Pool can help. We specialize in hard-to-find hot tub and spa parts and carry a wide range of replacement components for most major brands.
Here's how to reach us:
Phone: 1-855-248-0777
Email: fixmytub@gmail.com
Online: Browse our full parts catalogue
Send us your part number (if known), photos of the part, or your hot tub's make, model, and serial number — and we'll take it from there.
[Shop and Order at Western Tub and Pool]")
Product Description
2-1/2" Pump Union Kit — Union Nut, S Tailpiece & O-Ring for Hot Tubs and Spas
Got a leaking pump union? Don't drain your hot tub budget on a service call. This complete 2-1/2" pump union kit gives you everything you need to stop the leak and get your spa back up and running — fast.
Shop and order at Western Tub and Pool
Call us: 1-855-248-0777 | Email: fixmytub@gmail.com
[Shop Our Online Catalogue]
What's Included in This Kit
This kit contains all three components needed for a complete pump union replacement or repair on most standard hot tub and spa installations:
- 2-1/2" Union Nut — Buttress thread design for a secure, leak-resistant connection
- 2-1/2" S (Slip) Tailpiece — Fits directly into the pump port for a clean, watertight fit
- O-Ring / Gasket — Provides the compression seal between the tailpiece and union nut
No hunting down three separate parts. Everything arrives together, ready to install.
Product Specifications
|
Specification |
Detail |
|---|---|
|
Union Nut Thread Type |
2-1/2" Female Buttress Thread (FBT) |
|
Tailpiece Connection Type |
2-1/2" Slip (S) |
|
Tailpiece Dimensions |
Approx. 3.5" L x 3.5" W x 1.25" D |
|
Material |
Durable PVC / ABS plastic |
|
O-Ring Outer Diameter |
Approx. 3-7/16" OD |
|
Application |
Pump union (jet pump plumbing) |
|
Common Manufacturer |
Waterway Plastics |
Common Alternate Part Numbers: 415-6000 (union nut), 417-5970 (tailpiece), V40-421S (O-ring), WW4175970, 9175-10A, 610881
Note: This kit is designed for pump unions. If you need a union for a heater connection, a different tailpiece profile may be required. Not sure? Call us — we'll help you confirm the right part.
Compatible Hot Tub Brands and Models
This 2-1/2" pump union configuration is widely used across many popular hot tub and spa brands. Compatible models commonly include those manufactured by or controlled with systems from:
Brands:
- Waterway
- Balboa Water Group
- HydroQuip / Water Pro
- Jacuzzi
- Sundance Spas
- Caldera Spas
- Marquis Spas
- Master Spas
- Cal Spas
- Coleman / Maax Spas
- Dimension One Spas
- Artesian Spas
- Dynasty Spas
- Vita Spas
Compatible pump types commonly include:
- Waterway Hi-Flo, Executive, and EX2 Series
- Aqua Flo FMHP and XP2 Series
- BWG Vico Dura-Jet and Ultimax Series
- LX 48 and 56 Series Pumps
Not sure if this part fits your spa? Check your existing part number, or send us your spa's make, model, and serial number and we'll confirm compatibility for you.
Why This Is a Hard-to-Find Part — and Why We Stock It
Pump unions take a beating. Constant pressure cycles, chemical exposure, and UV degradation cause union nuts to crack and O-rings to harden and fail over time. When that happens, water finds a way out — and a small leak can become a big problem quickly.
The challenge? This part isn't always sitting on the shelf at your local hardware store. It requires the right thread profile (buttress thread, not standard pipe thread), the right slip size, and a matching O-ring. Getting just one of these wrong means the repair won't hold.
At Western Tub and Pool, we stock the parts that are genuinely hard to find — so you don't have to wait weeks or cobble together mismatched components.
How to Install Your New Pump Union
Step 1: Turn off power and drain the pump area
Switch off the spa at the breaker and allow pressure to release before touching any plumbing connections.
Step 2: Unscrew the old union nut
Turn the union nut counterclockwise to disconnect the pump from the plumbing line. If the nut is cracked or seized, a split-nut replacement tool may be required.
Step 3: Remove the old tailpiece and O-ring
Pull the tailpiece free from the pump port. Inspect and discard the old O-ring — never reuse a compressed or damaged O-ring.
Step 4: Install the new tailpiece and O-ring
Insert the new tailpiece into the pump port. Seat the new O-ring into its groove, applying a small amount of silicone lubricant for a better seal.
Step 5: Thread on the union nut and tighten
Hand-tighten the new union nut onto the buttress threads, then snug it with a strap wrench — do not over-torque. Restore power and check for leaks.
Need a hand? Western Tub and Pool offers free home tutorials on hot tub and spa maintenance. We're happy to walk you through the repair — call us at 1-855-248-0777.
Frequently Asked Questions
How do I know if this is the right union for my spa?
The best way to confirm is to check the part number printed or stamped on your existing union nut or tailpiece. Common numbers for this configuration include 415-6000 (nut) and 417-5970 (tailpiece). If your part number isn't visible, send us a photo along with your spa's make, model, and serial number and we'll identify it for you. Email fixmytub@gmail.com or call 1-855-248-0777.
Does this kit include the O-ring?
Yes. This listing includes the union nut, S tailpiece, and O-ring — all three components needed for a complete pump union assembly.
What is a buttress thread, and does it matter?
Yes, it matters. Buttress thread is a specialized thread profile used on spa pump unions — it is not interchangeable with standard NPT (pipe thread) fittings. Using the wrong thread type will result in cross-threading or a failed seal. This kit uses the correct 2-1/2" female buttress thread (FBT) profile.
My union nut is cracked and difficult to access. Can it still be replaced?
If your existing nut is cracked but still attached, a split-nut design may allow you to replace it without cutting the plumbing. We carry those as well — ask us about the right option for your situation.
Can I use this part on a heater union?
No. This tailpiece is designed for pump union connections and uses a small flange suited to pump ports. Heater unions use a different tailpiece profile. If you need a heater union, contact us and we'll point you to the correct part.
Do you offer help identifying parts I can't find elsewhere?
Absolutely. Hard-to-find parts are our specialty. Send us a photo of the part, your spa's serial number, or any part numbers you can find, and our team will track down what you need. Email fixmytub@gmail.com or browse our online catalogue.
Can't Find Your Part?
If you're not sure what you're looking for — or if you've already searched everywhere else — Western Tub and Pool can help. We specialize in hard-to-find hot tub and spa parts and carry a wide range of replacement components for most major brands.
Here's how to reach us:
- Phone: 1-855-248-0777
- Email:fixmytub@gmail.com
- Online: Browse our full parts catalogue
Send us your part number (if known), photos of the part, or your hot tub's make, model, and serial number — and we'll take it from there.
[Shop and Order at Western Tub and Pool]
![2-1/2" Pump Union Kit — Union Nut, S Tailpiece & O-Ring for Hot Tubs and Spas
Got a leaking pump union? Don't drain your hot tub budget on a service call. This complete 2-1/2" pump union kit gives you everything you need to stop the leak and get your spa back up and running — fast.
Shop and order at Western Tub and Pool
Call us: 1-855-248-0777 | Email: fixmytub@gmail.com
[Shop Our Online Catalogue]
What's Included in This Kit
This kit contains all three components needed for a complete pump union replacement or repair on most standard hot tub and spa installations:
2-1/2" Union Nut — Buttress thread design for a secure, leak-resistant connection
2-1/2" S (Slip) Tailpiece — Fits directly into the pump port for a clean, watertight fit
O-Ring / Gasket — Provides the compression seal between the tailpiece and union nut
No hunting down three separate parts. Everything arrives together, ready to install.
Product Specifications
Specification
Detail
Union Nut Thread Type
2-1/2" Female Buttress Thread (FBT)
Tailpiece Connection Type
2-1/2" Slip (S)
Tailpiece Dimensions
Approx. 3.5" L x 3.5" W x 1.25" D
Material
Durable PVC / ABS plastic
O-Ring Outer Diameter
Approx. 3-7/16" OD
Application
Pump union (jet pump plumbing)
Common Manufacturer
Waterway Plastics
Common Alternate Part Numbers: 415-6000 (union nut), 417-5970 (tailpiece), V40-421S (O-ring), WW4175970, 9175-10A, 610881
Note: This kit is designed for pump unions. If you need a union for a heater connection, a different tailpiece profile may be required. Not sure? Call us — we'll help you confirm the right part.
Compatible Hot Tub Brands and Models
This 2-1/2" pump union configuration is widely used across many popular hot tub and spa brands. Compatible models commonly include those manufactured by or controlled with systems from:
Brands:
Waterway
Balboa Water Group
HydroQuip / Water Pro
Jacuzzi
Sundance Spas
Caldera Spas
Marquis Spas
Master Spas
Cal Spas
Coleman / Maax Spas
Dimension One Spas
Artesian Spas
Dynasty Spas
Vita Spas
Compatible pump types commonly include:
Waterway Hi-Flo, Executive, and EX2 Series
Aqua Flo FMHP and XP2 Series
BWG Vico Dura-Jet and Ultimax Series
LX 48 and 56 Series Pumps
Not sure if this part fits your spa? Check your existing part number, or send us your spa's make, model, and serial number and we'll confirm compatibility for you.
Why This Is a Hard-to-Find Part — and Why We Stock It
Pump unions take a beating. Constant pressure cycles, chemical exposure, and UV degradation cause union nuts to crack and O-rings to harden and fail over time. When that happens, water finds a way out — and a small leak can become a big problem quickly.
The challenge? This part isn't always sitting on the shelf at your local hardware store. It requires the right thread profile (buttress thread, not standard pipe thread), the right slip size, and a matching O-ring. Getting just one of these wrong means the repair won't hold.
At Western Tub and Pool, we stock the parts that are genuinely hard to find — so you don't have to wait weeks or cobble together mismatched components.
How to Install Your New Pump Union
Step 1: Turn off power and drain the pump area
Switch off the spa at the breaker and allow pressure to release before touching any plumbing connections.
Step 2: Unscrew the old union nut
Turn the union nut counterclockwise to disconnect the pump from the plumbing line. If the nut is cracked or seized, a split-nut replacement tool may be required.
Step 3: Remove the old tailpiece and O-ring
Pull the tailpiece free from the pump port. Inspect and discard the old O-ring — never reuse a compressed or damaged O-ring.
Step 4: Install the new tailpiece and O-ring
Insert the new tailpiece into the pump port. Seat the new O-ring into its groove, applying a small amount of silicone lubricant for a better seal.
Step 5: Thread on the union nut and tighten
Hand-tighten the new union nut onto the buttress threads, then snug it with a strap wrench — do not over-torque. Restore power and check for leaks.
Need a hand? Western Tub and Pool offers free home tutorials on hot tub and spa maintenance. We're happy to walk you through the repair — call us at 1-855-248-0777.
Frequently Asked Questions
How do I know if this is the right union for my spa?
The best way to confirm is to check the part number printed or stamped on your existing union nut or tailpiece. Common numbers for this configuration include 415-6000 (nut) and 417-5970 (tailpiece). If your part number isn't visible, send us a photo along with your spa's make, model, and serial number and we'll identify it for you. Email fixmytub@gmail.com or call 1-855-248-0777.
Does this kit include the O-ring?
Yes. This listing includes the union nut, S tailpiece, and O-ring — all three components needed for a complete pump union assembly.
What is a buttress thread, and does it matter?
Yes, it matters. Buttress thread is a specialized thread profile used on spa pump unions — it is not interchangeable with standard NPT (pipe thread) fittings. Using the wrong thread type will result in cross-threading or a failed seal. This kit uses the correct 2-1/2" female buttress thread (FBT) profile.
My union nut is cracked and difficult to access. Can it still be replaced?
If your existing nut is cracked but still attached, a split-nut design may allow you to replace it without cutting the plumbing. We carry those as well — ask us about the right option for your situation.
Can I use this part on a heater union?
No. This tailpiece is designed for pump union connections and uses a small flange suited to pump ports. Heater unions use a different tailpiece profile. If you need a heater union, contact us and we'll point you to the correct part.
Do you offer help identifying parts I can't find elsewhere?
Absolutely. Hard-to-find parts are our specialty. Send us a photo of the part, your spa's serial number, or any part numbers you can find, and our team will track down what you need. Email fixmytub@gmail.com or browse our online catalogue.
Can't Find Your Part?
If you're not sure what you're looking for — or if you've already searched everywhere else — Western Tub and Pool can help. We specialize in hard-to-find hot tub and spa parts and carry a wide range of replacement components for most major brands.
Here's how to reach us:
Phone: 1-855-248-0777
Email: fixmytub@gmail.com
Online: Browse our full parts catalogue
Send us your part number (if known), photos of the part, or your hot tub's make, model, and serial number — and we'll take it from there.
[Shop and Order at Western Tub and Pool]](https://cdn11.bigcommerce.com/s-b7yzllubsu/images/stencil/500x659/products/4201/6242/SPA-WW400-5990__79687.1773441000.jpg?c=2 "2-1/2\" Pump Union Kit — Union Nut, S Tailpiece & O-Ring for Hot Tubs and Spas
Got a leaking pump union? Don't drain your hot tub budget on a service call. This complete 2-1/2\" pump union kit gives you everything you need to stop the leak and get your spa back up and running — fast.
Shop and order at Western Tub and Pool
Call us: 1-855-248-0777 | Email: fixmytub@gmail.com
[Shop Our Online Catalogue]
What's Included in This Kit
This kit contains all three components needed for a complete pump union replacement or repair on most standard hot tub and spa installations:
2-1/2\" Union Nut — Buttress thread design for a secure, leak-resistant connection
2-1/2\" S (Slip) Tailpiece — Fits directly into the pump port for a clean, watertight fit
O-Ring / Gasket — Provides the compression seal between the tailpiece and union nut
No hunting down three separate parts. Everything arrives together, ready to install.
Product Specifications
Specification
Detail
Union Nut Thread Type
2-1/2\" Female Buttress Thread (FBT)
Tailpiece Connection Type
2-1/2\" Slip (S)
Tailpiece Dimensions
Approx. 3.5\" L x 3.5\" W x 1.25\" D
Material
Durable PVC / ABS plastic
O-Ring Outer Diameter
Approx. 3-7/16\" OD
Application
Pump union (jet pump plumbing)
Common Manufacturer
Waterway Plastics
Common Alternate Part Numbers: 415-6000 (union nut), 417-5970 (tailpiece), V40-421S (O-ring), WW4175970, 9175-10A, 610881
Note: This kit is designed for pump unions. If you need a union for a heater connection, a different tailpiece profile may be required. Not sure? Call us — we'll help you confirm the right part.
Compatible Hot Tub Brands and Models
This 2-1/2\" pump union configuration is widely used across many popular hot tub and spa brands. Compatible models commonly include those manufactured by or controlled with systems from:
Brands:
Waterway
Balboa Water Group
HydroQuip / Water Pro
Jacuzzi
Sundance Spas
Caldera Spas
Marquis Spas
Master Spas
Cal Spas
Coleman / Maax Spas
Dimension One Spas
Artesian Spas
Dynasty Spas
Vita Spas
Compatible pump types commonly include:
Waterway Hi-Flo, Executive, and EX2 Series
Aqua Flo FMHP and XP2 Series
BWG Vico Dura-Jet and Ultimax Series
LX 48 and 56 Series Pumps
Not sure if this part fits your spa? Check your existing part number, or send us your spa's make, model, and serial number and we'll confirm compatibility for you.
Why This Is a Hard-to-Find Part — and Why We Stock It
Pump unions take a beating. Constant pressure cycles, chemical exposure, and UV degradation cause union nuts to crack and O-rings to harden and fail over time. When that happens, water finds a way out — and a small leak can become a big problem quickly.
The challenge? This part isn't always sitting on the shelf at your local hardware store. It requires the right thread profile (buttress thread, not standard pipe thread), the right slip size, and a matching O-ring. Getting just one of these wrong means the repair won't hold.
At Western Tub and Pool, we stock the parts that are genuinely hard to find — so you don't have to wait weeks or cobble together mismatched components.
How to Install Your New Pump Union
Step 1: Turn off power and drain the pump area
Switch off the spa at the breaker and allow pressure to release before touching any plumbing connections.
Step 2: Unscrew the old union nut
Turn the union nut counterclockwise to disconnect the pump from the plumbing line. If the nut is cracked or seized, a split-nut replacement tool may be required.
Step 3: Remove the old tailpiece and O-ring
Pull the tailpiece free from the pump port. Inspect and discard the old O-ring — never reuse a compressed or damaged O-ring.
Step 4: Install the new tailpiece and O-ring
Insert the new tailpiece into the pump port. Seat the new O-ring into its groove, applying a small amount of silicone lubricant for a better seal.
Step 5: Thread on the union nut and tighten
Hand-tighten the new union nut onto the buttress threads, then snug it with a strap wrench — do not over-torque. Restore power and check for leaks.
Need a hand? Western Tub and Pool offers free home tutorials on hot tub and spa maintenance. We're happy to walk you through the repair — call us at 1-855-248-0777.
Frequently Asked Questions
How do I know if this is the right union for my spa?
The best way to confirm is to check the part number printed or stamped on your existing union nut or tailpiece. Common numbers for this configuration include 415-6000 (nut) and 417-5970 (tailpiece). If your part number isn't visible, send us a photo along with your spa's make, model, and serial number and we'll identify it for you. Email fixmytub@gmail.com or call 1-855-248-0777.
Does this kit include the O-ring?
Yes. This listing includes the union nut, S tailpiece, and O-ring — all three components needed for a complete pump union assembly.
What is a buttress thread, and does it matter?
Yes, it matters. Buttress thread is a specialized thread profile used on spa pump unions — it is not interchangeable with standard NPT (pipe thread) fittings. Using the wrong thread type will result in cross-threading or a failed seal. This kit uses the correct 2-1/2\" female buttress thread (FBT) profile.
My union nut is cracked and difficult to access. Can it still be replaced?
If your existing nut is cracked but still attached, a split-nut design may allow you to replace it without cutting the plumbing. We carry those as well — ask us about the right option for your situation.
Can I use this part on a heater union?
No. This tailpiece is designed for pump union connections and uses a small flange suited to pump ports. Heater unions use a different tailpiece profile. If you need a heater union, contact us and we'll point you to the correct part.
Do you offer help identifying parts I can't find elsewhere?
Absolutely. Hard-to-find parts are our specialty. Send us a photo of the part, your spa's serial number, or any part numbers you can find, and our team will track down what you need. Email fixmytub@gmail.com or browse our online catalogue.
Can't Find Your Part?
If you're not sure what you're looking for — or if you've already searched everywhere else — Western Tub and Pool can help. We specialize in hard-to-find hot tub and spa parts and carry a wide range of replacement components for most major brands.
Here's how to reach us:
Phone: 1-855-248-0777
Email: fixmytub@gmail.com
Online: Browse our full parts catalogue
Send us your part number (if known), photos of the part, or your hot tub's make, model, and serial number — and we'll take it from there.
[Shop and Order at Western Tub and Pool]")
![Waterway 2.5" x 2" Pump Union for Viper Pump with Gasket (400-5990)
Stop your spa leak fast with the exact OEM-spec union your Waterway Viper pump needs. This genuine Waterway replacement pump union delivers a watertight seal at the suction side of your pump — and it ships with a matching gasket included.
Shop and order at Western Tub and Pool
Call us: 1-855-248-0777 | Email: fixmytub@gmail.com
[Order Now] [Call Us Today]
What Is This Part?
The Waterway 2.5" x 2" Pump Union (Part # 400-5990) is a suction-side pump union fitting designed for Waterway Viper, XP3, and select Executive series hot tub pumps. It connects your spa's 2" suction plumbing to the 2.5" threaded wet end of your pump, forming a secure, leak-free joint.
A matching gasket is included with every unit — so you have everything you need to complete the repair in one purchase.
Product Specifications
Specification
Detail
Manufacturer
Waterway
Part Number
400-5990
UPC / GTIN
806105082145
Connection Type
2" Slip (glue) x 2.5" Female Buttress Thread
Pipe Side (slip)
Accepts 2" pipe or fitting (~2 3/8" O.D.)
Pump Side (threaded)
Screws onto 2.5" wet end (~3 5/8" O.D. across threads)
Gasket Included
Yes
Product Weight
0.43 lbs
Shipping Dimensions
2.25" x 4.25" x 4.25"
Shipping Weight
0.40 lbs
How It Works
This union is a two-part fitting — a nut and tailpiece — that allows you to easily connect and disconnect your pump from the spa plumbing without cutting pipe.
The slip side accepts a 2" PVC pipe or fitting, which is glued in place
The threaded side screws directly onto the 2.5" threaded wet end (volute) of your pump
The included gasket seats between the two halves to create a watertight seal
When you need to service your pump, simply unscrew the union nut — no cutting required
Compatible Pumps and Hot Tub Models
This union is designed for use with hot tubs and spas equipped with the following pumps:
Compatible Pumps
Waterway Viper series pumps (48 and 56 frame) — 2.5" x 2.5" wet end port
Aqua-Flo XP3 series pumps (48 and 56 frame) — 2.5" x 2.5" wet end port
Waterway Executive series pumps — select models (verify before ordering)
Hot Tub Brands That Commonly Use These Pumps
Many hot tub manufacturers source Waterway and Aqua-Flo pumps as original equipment, including but not limited to:
Strong Spas
Artesian Spas
PDC Spas
Cal Spas
Dynasty Spas
Sundance Spas (select models)
Jacuzzi (select older models)
Marquis Spas (select models)
American Whirlpool
Dimension One Spas (select models)
Not sure if this is the right part for your spa? The pump and plumbing configuration can vary between models and production years. We strongly recommend verifying your part number, pump model, or wet end port size before ordering. See our FAQ section below for guidance.
Why Order from Western Tub and Pool?
Hard-to-Find Parts, Found
We specialize in locating and supplying replacement parts that are difficult to source elsewhere. If you've been searching without success, chances are we have it — or we can help you find it.
Expert Guidance
Not confident you have the right part? Our team has decades of experience diagnosing spa and hot tub issues. Call or email us and we'll walk you through it.
Free Home Tutorials
New to hot tub maintenance? Western Tub and Pool offers free in-home tutorials to help you understand your spa, your water care, and your repair options — because a well-maintained hot tub is a safe and enjoyable one.
Trusted Local Service
We're a real business with real people. When you contact us, you speak to someone who knows hot tubs inside and out.
Frequently Asked Questions
How do I know if this is the correct pump union for my hot tub?
The best way to confirm compatibility is to check the existing union on your pump. Measure the outside diameter of your pump's wet end threads — if it measures approximately 3 5/8" across, this union is likely the correct fit. You can also check the stamped part number on your existing union, or call us at 1-855-248-0777 and we'll help you confirm.
Can I send you photos of my part to confirm the fit?
Absolutely. Email clear photos of your existing union, along with your hot tub's make, model, and serial number, to fixmytub@gmail.com. Our team will review your images and confirm whether this part is the right match before you order.
Is the gasket included, or do I need to order it separately?
The gasket is included with this union. You will not need to purchase it separately.
Do I need special tools to replace a pump union?
In most cases, no. Pump unions are designed for hand-tightening and removal. You may need basic plumbing supplies such as PVC primer and cement if you are also replacing the tailpiece or re-gluing the slip side into new pipe.
What if I can't find my part number?
That's what we're here for. Send us an email to fixmytub@gmail.com with your hot tub's make, model, and serial number, along with photos of the part you need. We'll identify the correct replacement and get back to you promptly.
Do you carry other Waterway pump parts?
Yes. We carry a wide range of Waterway pump components, including wet ends, impellers, O-rings, seals, and more. Browse our online catalogue or give us a call to check availability.
Can't Find the Right Part? We Can Help.
Tracking down the right hot tub replacement part can be frustrating — especially for older or discontinued models. At Western Tub and Pool, helping customers find hard-to-locate parts is one of our specialties.
Here's how to get the fastest answer:
Have your hot tub's make, model, and serial number ready
Check your existing part for a stamped part number
Take a few clear photos of the part and the surrounding plumbing area
Send everything to fixmytub@gmail.com or call 1-855-248-0777
We'll do the research and get back to you quickly.
Shop and Order at Western Tub and Pool
Whether you know exactly what you need or you're still trying to figure it out, the team at Western Tub and Pool is ready to help you get your hot tub back up and running.
Call us: 1-855-248-0777
Email us: fixmytub@gmail.com
[Order This Part Now] [Browse Our Full Parts Catalogue]](https://cdn11.bigcommerce.com/s-b7yzllubsu/images/stencil/500x659/products/4200/6241/SPA-WW400-5990__14767.1773436263.jpg?c=2 "Waterway 2.5\" x 2\" Pump Union for Viper Pump with Gasket (400-5990)
Stop your spa leak fast with the exact OEM-spec union your Waterway Viper pump needs. This genuine Waterway replacement pump union delivers a watertight seal at the suction side of your pump — and it ships with a matching gasket included.
Shop and order at Western Tub and Pool
Call us: 1-855-248-0777 | Email: fixmytub@gmail.com
[Order Now] [Call Us Today]
What Is This Part?
The Waterway 2.5\" x 2\" Pump Union (Part # 400-5990) is a suction-side pump union fitting designed for Waterway Viper, XP3, and select Executive series hot tub pumps. It connects your spa's 2\" suction plumbing to the 2.5\" threaded wet end of your pump, forming a secure, leak-free joint.
A matching gasket is included with every unit — so you have everything you need to complete the repair in one purchase.
Product Specifications
Specification
Detail
Manufacturer
Waterway
Part Number
400-5990
UPC / GTIN
806105082145
Connection Type
2\" Slip (glue) x 2.5\" Female Buttress Thread
Pipe Side (slip)
Accepts 2\" pipe or fitting (~2 3/8\" O.D.)
Pump Side (threaded)
Screws onto 2.5\" wet end (~3 5/8\" O.D. across threads)
Gasket Included
Yes
Product Weight
0.43 lbs
Shipping Dimensions
2.25\" x 4.25\" x 4.25\"
Shipping Weight
0.40 lbs
How It Works
This union is a two-part fitting — a nut and tailpiece — that allows you to easily connect and disconnect your pump from the spa plumbing without cutting pipe.
The slip side accepts a 2\" PVC pipe or fitting, which is glued in place
The threaded side screws directly onto the 2.5\" threaded wet end (volute) of your pump
The included gasket seats between the two halves to create a watertight seal
When you need to service your pump, simply unscrew the union nut — no cutting required
Compatible Pumps and Hot Tub Models
This union is designed for use with hot tubs and spas equipped with the following pumps:
Compatible Pumps
Waterway Viper series pumps (48 and 56 frame) — 2.5\" x 2.5\" wet end port
Aqua-Flo XP3 series pumps (48 and 56 frame) — 2.5\" x 2.5\" wet end port
Waterway Executive series pumps — select models (verify before ordering)
Hot Tub Brands That Commonly Use These Pumps
Many hot tub manufacturers source Waterway and Aqua-Flo pumps as original equipment, including but not limited to:
Strong Spas
Artesian Spas
PDC Spas
Cal Spas
Dynasty Spas
Sundance Spas (select models)
Jacuzzi (select older models)
Marquis Spas (select models)
American Whirlpool
Dimension One Spas (select models)
Not sure if this is the right part for your spa? The pump and plumbing configuration can vary between models and production years. We strongly recommend verifying your part number, pump model, or wet end port size before ordering. See our FAQ section below for guidance.
Why Order from Western Tub and Pool?
Hard-to-Find Parts, Found
We specialize in locating and supplying replacement parts that are difficult to source elsewhere. If you've been searching without success, chances are we have it — or we can help you find it.
Expert Guidance
Not confident you have the right part? Our team has decades of experience diagnosing spa and hot tub issues. Call or email us and we'll walk you through it.
Free Home Tutorials
New to hot tub maintenance? Western Tub and Pool offers free in-home tutorials to help you understand your spa, your water care, and your repair options — because a well-maintained hot tub is a safe and enjoyable one.
Trusted Local Service
We're a real business with real people. When you contact us, you speak to someone who knows hot tubs inside and out.
Frequently Asked Questions
How do I know if this is the correct pump union for my hot tub?
The best way to confirm compatibility is to check the existing union on your pump. Measure the outside diameter of your pump's wet end threads — if it measures approximately 3 5/8\" across, this union is likely the correct fit. You can also check the stamped part number on your existing union, or call us at 1-855-248-0777 and we'll help you confirm.
Can I send you photos of my part to confirm the fit?
Absolutely. Email clear photos of your existing union, along with your hot tub's make, model, and serial number, to fixmytub@gmail.com. Our team will review your images and confirm whether this part is the right match before you order.
Is the gasket included, or do I need to order it separately?
The gasket is included with this union. You will not need to purchase it separately.
Do I need special tools to replace a pump union?
In most cases, no. Pump unions are designed for hand-tightening and removal. You may need basic plumbing supplies such as PVC primer and cement if you are also replacing the tailpiece or re-gluing the slip side into new pipe.
What if I can't find my part number?
That's what we're here for. Send us an email to fixmytub@gmail.com with your hot tub's make, model, and serial number, along with photos of the part you need. We'll identify the correct replacement and get back to you promptly.
Do you carry other Waterway pump parts?
Yes. We carry a wide range of Waterway pump components, including wet ends, impellers, O-rings, seals, and more. Browse our online catalogue or give us a call to check availability.
Can't Find the Right Part? We Can Help.
Tracking down the right hot tub replacement part can be frustrating — especially for older or discontinued models. At Western Tub and Pool, helping customers find hard-to-locate parts is one of our specialties.
Here's how to get the fastest answer:
Have your hot tub's make, model, and serial number ready
Check your existing part for a stamped part number
Take a few clear photos of the part and the surrounding plumbing area
Send everything to fixmytub@gmail.com or call 1-855-248-0777
We'll do the research and get back to you quickly.
Shop and Order at Western Tub and Pool
Whether you know exactly what you need or you're still trying to figure it out, the team at Western Tub and Pool is ready to help you get your hot tub back up and running.
Call us: 1-855-248-0777
Email us: fixmytub@gmail.com
[Order This Part Now] [Browse Our Full Parts Catalogue]")
![Effortlessly Upgrade Your Pump Connections
Simplify your plumbing setup with our 2 to 2.5-inch Pump Connector Converter. Designed for precision, this threaded buttress connector ensures a seamless transition for your 2 x 2 pump connection to a 2 x 2.5-inch size.
[Order Now at Western Tub and Pool 1-855-248-0777 ]
Built for Flexibility and Performance
Tackle your plumbing challenges without the hassle. Our pump connector converter offers a durable, reliable solution for adapting your system with ease.
Key Benefits
Universal Compatibility
Perfect for most 2 x 2 pump connections, making conversions to 2 x 2.5-inch quick and easy.
Durable Threaded Design
Crafted with precision for a snug, secure fit to prevent leaks.
High-Quality Materials
Built with heavy-duty materials to ensure long-term reliability and performance under rigorous conditions.
Simple Installation
No need for additional tools or expert help. Save time and effort with straightforward installation instructions.
How It Works
1. Connect
Thread the buttress connector onto your 2 x 2 pump connection.
2. Adapt
Easily extend to a 2 x 2.5-inch connection, ensuring perfect compatibility.
3. Get Back to Work
Complete your plumbing application hassle-free and continue running efficiently.
Make Every Connection Count
Don’t let incompatible connectors slow you down. Upgrade to our 2 to 2.5-inch Pump Connector Converter and simplify your plumbing tasks today.
[ Order Now at Western Tub and pool 1-855-248-0777 ]](https://cdn11.bigcommerce.com/s-b7yzllubsu/images/stencil/500x659/products/3791/5353/415-6010__78522.1754174514.png?c=2 "Effortlessly Upgrade Your Pump Connections
Simplify your plumbing setup with our 2 to 2.5-inch Pump Connector Converter. Designed for precision, this threaded buttress connector ensures a seamless transition for your 2 x 2 pump connection to a 2 x 2.5-inch size.
[Order Now at Western Tub and Pool 1-855-248-0777 ]
Built for Flexibility and Performance
Tackle your plumbing challenges without the hassle. Our pump connector converter offers a durable, reliable solution for adapting your system with ease.
Key Benefits
Universal Compatibility
Perfect for most 2 x 2 pump connections, making conversions to 2 x 2.5-inch quick and easy.
Durable Threaded Design
Crafted with precision for a snug, secure fit to prevent leaks.
High-Quality Materials
Built with heavy-duty materials to ensure long-term reliability and performance under rigorous conditions.
Simple Installation
No need for additional tools or expert help. Save time and effort with straightforward installation instructions.
How It Works
1. Connect
Thread the buttress connector onto your 2 x 2 pump connection.
2. Adapt
Easily extend to a 2 x 2.5-inch connection, ensuring perfect compatibility.
3. Get Back to Work
Complete your plumbing application hassle-free and continue running efficiently.
Make Every Connection Count
Don’t let incompatible connectors slow you down. Upgrade to our 2 to 2.5-inch Pump Connector Converter and simplify your plumbing tasks today.
[ Order Now at Western Tub and pool 1-855-248-0777 ]")
![Effortlessly Upgrade Your Pump Connections
Simplify your plumbing setup with our 2 to 2.5-inch Pump Connector Converter. Designed for precision, this threaded buttress connector ensures a seamless transition for your 2 x 2 pump connection to a 2 x 2.5-inch size.
[Order Now at Western Tub and Pool 1-855-248-0777 ]
Built for Flexibility and Performance
Tackle your plumbing challenges without the hassle. Our pump connector converter offers a durable, reliable solution for adapting your system with ease.
Key Benefits
Universal Compatibility
Perfect for most 2 x 2 pump connections, making conversions to 2 x 2.5-inch quick and easy.
Durable Threaded Design
Crafted with precision for a snug, secure fit to prevent leaks.
High-Quality Materials
Built with heavy-duty materials to ensure long-term reliability and performance under rigorous conditions.
Simple Installation
No need for additional tools or expert help. Save time and effort with straightforward installation instructions.
How It Works
1. Connect
Thread the buttress connector onto your 2 x 2 pump connection.
2. Adapt
Easily extend to a 2 x 2.5-inch connection, ensuring perfect compatibility.
3. Get Back to Work
Complete your plumbing application hassle-free and continue running efficiently.
Make Every Connection Count
Don’t let incompatible connectors slow you down. Upgrade to our 2 to 2.5-inch Pump Connector Converter and simplify your plumbing tasks today.
[ Order Now at Western Tub and pool 1-855-248-0777 ]](https://cdn11.bigcommerce.com/s-b7yzllubsu/images/stencil/500x659/products/3791/5354/Effortlessly_Upgrade_Your_Pump_Connections_1-855-248-0777_western_tub_and_pool___95501.1754174516.png?c=2 "Effortlessly Upgrade Your Pump Connections
Simplify your plumbing setup with our 2 to 2.5-inch Pump Connector Converter. Designed for precision, this threaded buttress connector ensures a seamless transition for your 2 x 2 pump connection to a 2 x 2.5-inch size.
[Order Now at Western Tub and Pool 1-855-248-0777 ]
Built for Flexibility and Performance
Tackle your plumbing challenges without the hassle. Our pump connector converter offers a durable, reliable solution for adapting your system with ease.
Key Benefits
Universal Compatibility
Perfect for most 2 x 2 pump connections, making conversions to 2 x 2.5-inch quick and easy.
Durable Threaded Design
Crafted with precision for a snug, secure fit to prevent leaks.
High-Quality Materials
Built with heavy-duty materials to ensure long-term reliability and performance under rigorous conditions.
Simple Installation
No need for additional tools or expert help. Save time and effort with straightforward installation instructions.
How It Works
1. Connect
Thread the buttress connector onto your 2 x 2 pump connection.
2. Adapt
Easily extend to a 2 x 2.5-inch connection, ensuring perfect compatibility.
3. Get Back to Work
Complete your plumbing application hassle-free and continue running efficiently.
Make Every Connection Count
Don’t let incompatible connectors slow you down. Upgrade to our 2 to 2.5-inch Pump Connector Converter and simplify your plumbing tasks today.
[ Order Now at Western Tub and pool 1-855-248-0777 ]")