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Heater Split Nut 0121108015 - Bubbles Supply

Heater Split Nut 0121108015

Part #: 0121108015

$5.87
In stock — ships today
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🔒 Secure checkout↩️ 30-day returns✅ 1-year warranty
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1-year warrantySame-day ship before 3pm CTPerfect Fit Guarantee30-day returns

About this union/fitting

The Magic Plastics Heater Split Nut 0121108015 is a genuine OEM replacement part designed for spa heater unions with 1-1/2" FBT connections and large flange configurations. This critical component creates a secure, watertight seal between heater elements and plumbing, preventing costly leaks and maintaining optimal water flow through your spa's heating system.

Engineered to Magic Plastics' exact specifications, this split nut delivers the precise fit and durability your spa demands. At Bubbles Supply, we guarantee an exact fit for your heater assembly, back every part with a full 1-year warranty, and ship same-day to get your spa running fast. The large flange design provides enhanced stability and sealing performance compared to standard unions. Always verify your existing heater union size and thread type before ordering to ensure proper fitment.

Exact part number

0121108015

Save this for ordering or warranty claims

Also known as / Replaces

This part replaces or is interchangeable with:

  • heater union nut
  • heater union split nut
  • split union nut
  • union tail piece nut

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

Technical specifications

Union size
1-1/2 inch FBT (Female Buttress Thread)

Plumbing notes

  • Union size: 1-1/2 inch FBT (Female Buttress Thread)

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:

  • Water leaking at heater union connection
  • Split nut cracked or broken and unable to hold seal
  • Union won't tighten or stay secure
  • Heater assembly leaking after repeated thermal cycling
  • Visible damage or stress fractures on existing union nut

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

Before you buy — quick checklist

  • Confirm your existing heater union uses 1-1/2" FBT (Female Buttress Thread) connections — not all heater unions share the same thread type
  • Verify your union has a large flange configuration — compare flange diameter against your existing nut before ordering
  • Inspect the mating union body and o-ring — a bad nut often means the o-ring or union body is also damaged and should be replaced at the same time
  • Check whether you need just the split nut or the full union assembly — this is the nut only, not the complete union
  • Shut off all power and water to the heater before disassembly

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

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

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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