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Pump Union 400-1940 - Bubbles Supply

Pump Union 400-1940

Part #: 400-1940

$3.38
In stock — ships today
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1-year warrantySame-day ship before 3pm CTPerfect Fit Guarantee30-day returns

About this union/fitting

This Waterway pump union (part #400-1940) provides a secure, removable connection for spa pumps with 1" female buttress thread (FBT) to 3/4" barb fittings. As an OEM Waterway component, it ensures reliable performance in hot tub plumbing systems where maintenance access is essential.

Built to Waterway's exacting standards, this union features durable construction that withstands spa chemicals and temperature fluctuations. At Bubbles Supply, we guarantee exact fit compatibility and back every union with our 1-year warranty. Most orders ship same day for minimal downtime. Always verify your existing union's thread type and barb size before ordering—FBT threads have a distinctive buttress profile that differs from standard pipe threads.

Exact part number

400-1940

Save this for ordering or warranty claims

Also known as / Replaces

This part replaces or is interchangeable with:

  • 1-inch buttress union
  • FBT to barb union
  • Pump union
  • spa pump union fitting

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

Technical specifications

Union size
1 inch FBT (female buttress thread) to 3/4 inch barb

Plumbing notes

  • Union size: 1 inch FBT (female buttress thread) to 3/4 inch barb

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:

  • Active water leak at pump union connection
  • Union cracked or weeping after chemical exposure
  • Unable to disconnect pump for service due to stripped or damaged union
  • Broken union body preventing proper pump removal
  • Visible thread damage on existing FBT union

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

Before you buy — quick checklist

  • Confirm your existing union uses FBT (female buttress thread) — buttress threads have a flat-sided, asymmetrical profile distinct from standard NPT pipe threads
  • Verify the barb size on your current plumbing — this union is 3/4 inch barb, not 1 inch or 1.5 inch
  • Inspect both halves of your existing union — this listing is for the union body; confirm whether you need just one half or the complete assembly
  • Check that your hose or flex pipe inner diameter matches 3/4 inch barb sizing before ordering
  • Confirm this is a Waterway-brand pump installation — FBT thread unions are not universally interchangeable across all spa pump brands

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 (400-1940)
  • O-ring (verify inclusion with product listing at time of order)

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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