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Pump Union 400-4230 - Bubbles Supply

Pump Union 400-4230

Part #: 400-4230

$19.28
In stock — ships today
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1-year warrantySame-day ship before 3pm CTPerfect Fit Guarantee30-day returns

About this union/fitting

The Waterway Pump Union 400-4230 is an essential plumbing connection component designed for spa and hot tub pump installations. This OEM replacement union features 1-1/2" FBT (Female Buttress Thread) x 1-1/2" FPT (Female Pipe Thread) connections, providing a secure, leak-proof joint between your pump and plumbing system.

Engineered to Waterway's exacting standards, this union ensures reliable performance and proper water flow in your spa's circulation system. At Bubbles Supply, we guarantee an exact fit for your application and offer same-day shipping on in-stock items, backed by our comprehensive 1-year warranty. The precision-threaded connections eliminate the guesswork often associated with aftermarket alternatives, giving you confidence in your repair.

Before installation, verify your existing pump union configuration and thread type to ensure proper fitment. Hand-tighten plus one quarter turn with appropriate tools to achieve optimal seal without over-torquing.

Exact part number

400-4230

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Also known as / Replaces

This part replaces or is interchangeable with:

  • 1.5 inch pump union
  • 400-4230 union
  • FBT union
  • pump union
  • spa pump union

Looking for an older part number? Check our supersession lookup tool

Technical specifications

Union size
1-1/2 inch

Plumbing notes

  • Union size: 1-1/2 inch

Need help measuring? Email hello@bubblessupply.com with a photo of your existing plumbing.

Common symptoms this part fixes

If your spa is showing any of these signs, this part is likely your fix:

  • Slow drip or steady leak at pump inlet or outlet connection
  • Water pooling under the equipment bay near the pump
  • Loss of prime caused by air infiltration at a cracked or cross-threaded union
  • Visible cracks or stress fractures in the existing union body
  • Stripped or damaged threads preventing a proper seal

Not sure if this is your problem? Try our diagnostic centre or .

Before you buy — quick checklist

  • Confirm your existing union uses 1-1/2" FBT (Female Buttress Thread) on one end — buttress thread is not interchangeable with standard NPT
  • Verify the mating side requires 1-1/2" FPT (Female Pipe Thread) — measure or check your pump port and plumbing pipe size before ordering
  • Inspect whether the leak is at the union itself or at the pump volute port — a damaged volute requires a different fix
  • Check that your existing union half (the piece that stays on the pump) is also in good condition; you may need to replace both halves
  • Have a spa-safe thread sealant or Teflon tape on hand for the FPT side — the FBT side seals with the union O-ring only, no tape needed

Reading the checklist now prevents 90% of returns. Worth the 60 seconds.

Install difficulty: Easy — DIY-friendlyTypically 15-30 minutes

What's in the box

  • Pump union body (400-4230)
  • Union O-ring

If your order is missing any items listed above, contact hello@bubblessupply.com within 48 hours of delivery.

Warranty

1 year manufacturer warranty against defects

Covers manufacturing defects. Does not cover improper installation, normal wear, or accidental damage.

Warranty claims: warranty@bubblessupply.com

Perfect Fit Guarantee

Ordered with our help and the part doesn't fit? Contact us before installation. We'll resolve it with an exchange, replacement recommendation, or return approval.

Learn about our Perfect Fit Guarantee →

Shipping

We ship across the US and Canada. US orders ship from our US warehouse to US customers; Canadian orders ship from our Canadian warehouse to Canadian customers — no cross-border shipping, no surprise duties. In-stock orders placed before 3pm CT ship same day. Standard shipping $9.95 flat rate. Free shipping on orders over $200. Express options available at checkout.

Returns

30-day hassle-free returns on unused parts in original packaging. Contact us before returning to receive your RMA number.

Frequently asked questions

Check the Compatibility section above to confirm fitment for your spa brand and model. If your model is not listed, use our fitment selector at /pages/find-my-part or ask our parts AI for a personalized recommendation.

In-stock orders placed before 3pm CT ship the same day. You will receive tracking information by email as soon as your order ships.

We accept returns within 30 days of delivery for unused items in original packaging. Email returns@bubblessupply.com with your order number to start a return. Installed electrical parts cannot be returned for safety reasons.

Yes, all new parts come with a 1-year warranty against manufacturing defects. Warranty does not cover damage from improper installation or normal wear and tear.

Customer reviews

AI Fitment Assistant

Tell us your spa model and we will confirm this part fits before you buy.

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