Thermcore Products 86-02370 uni-nut for a 3 inch heater tubeThermcore Products Uni-Nut for 3" Heater Tube, 86-02370 In stock$1299
Thermcore Products 86-02370 uni-nut for a 3 inch heater tube
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Thermcore Products Uni-Nut for 3" Heater Tube, 86-02370

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$1299
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Quick overview

  • For a 3 inch heater tube The union nut that clamps a 3 inch spa heater tube to its manifold.
  • 4 inch outside diameter Measure across the outside of the nut to confirm the match.
  • 3-5/8 inch threads The thread diameter the nut turns onto.
  • 3-3/8 inch inside flange The inner flange that bears on the heater tube flange.
  • Nut only The o-ring or gasket that seals the joint is a separate part.
  • Common wear point Heater nuts crack from heat cycling and overtightening, and a cracked one will not hold a seal.
Full description and specifications ↓

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Product details

Part number 86-02370 is the uni-nut for a 3 inch heater tube. It measures 4 inch across the outside, turns onto 3-5/8 inch threads, and has a 3-3/8 inch inside flange.

What it does

The uni-nut is the large threaded collar that draws a heater tube up against its mating flange and holds the joint together. The nut supplies all the clamping force in that connection, so if it is cracked, stripped or distorted the joint will weep no matter how good the o-ring is.

Fitting

The seal itself is made by a separate 3 inch o-ring gasket, which is not part of this listing. Fit a fresh o-ring at the same time, seat the nut square, and bring it up hand tight. These nuts split when they are wrenched down, so extra torque buys a leak rather than a seal.

Specifications
Brand Thermcore Products
Manufacturer part number 86-02370
Type Heater uni-nut
For 3 inch heater tube
Outside diameter 4 inch
Threads 3-5/8 inch
Inside flange 3-3/8 inch
Shipping weight 0.2 lb
Ships Parcel

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Customer reviews

Questions and answers

What people ask about this product, answered by our pool techs.

What size heater tube does it fit?
A 3 inch heater tube. The nut itself is 4 inch OD with 3-5/8 inch threads and a 3-3/8 inch inside flange.
Does a gasket or o-ring come with it?
No. This listing is the uni-nut on its own. The 3 inch o-ring gasket that seals the joint is ordered separately.
How do I check it is the right nut?
Measure the outside diameter of the old nut and the thread diameter it turns onto. This one is 4 inch OD on 3-5/8 inch threads.
Why do these crack?
Repeated heat cycling makes the plastic brittle, and overtightening finishes the job. Hand tight against a fresh o-ring is enough, so avoid using a wrench on the replacement.
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