MasterTemp Unions

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cdchris1

Well-known member
Apr 28, 2016
103
SW Chicago/IL
Pool Size
15000
Surface
Fiberglass
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
I am trying to make some fittings so I can descale my Pentair MasterTemp heater. I was wondering if anyone knows if the nuts for the union are a proprietary thread (like the Pentair salt cells), or if they are a standard thread that I could pick up at Home Depot. If they are proprietary, are they the same as those for a Clean and Clear filter? I really only need the nuts, and saw the filter ones on-line cheaper than the whole heater unions. Just wondering before I order anything. Thanks!
 
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This part unscrews.

pentair-6290-52505.jpg

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So those are a standard 2" NTP? I thought those would be proprietary as well. I can make that work then without having to by the unions.

Why should I remove the thermal regulator?
 
I am pretty sure that the threads are standard 2" NPT.

Edit - Note: NPT meaning National Pipe Thread (NPT also refers to National Pipe Taper). The thread is probably straight and not tapered.

The thermal regulator blocks flow through the heat exchanger until the water gets hot.

So, the descaling mix will not circulate through the heat exchanger with the thermal regulator in.

It will a little bit because it is not a perfect seal, so it will work with the thermal regulator in, but not as well as with it out.

You should have new O-rings for the part that unscrews because the O-ring will sometimes be compressed and it won’t reseal properly.
 
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So I need to by the unions (item 23)? Or can I unscrew the connector tube (item 14) and screw in a standard 2" NPT fitting? - Sorry, just saw your other reply. Thanks!
 
cdchris1 said:
So I need to by the unions (item 23)? Or can I unscrew the connector tube (item 14) and screw in a standard 2" NPT fitting? - Sorry, just saw your other reply. Thanks!
Click to expand...
You should be able to do it either way.

Help finding replacement pvc fitting

Anyone know what this is called and where to find it? It was used to connect to Pentair pool heater. 2” pvc cracked
www.troublefreepool.com www.troublefreepool.com

Pentair Pool & Spa 2 PK/ Half Union 2" Slip - 42001-0402 - INYOPools.com

www.inyopools.com www.inyopools.com

www.tcpoolequipment.com

Sta-Rite Max-E-Therm Pool Heater Union Kit | 42001-0402

#42001-0402 Sta-Rite Max-E-Therm Pool Heater 400 Manifold Union Kit
www.tcpoolequipment.com
 
If you unscrew the connector tubes, I would want to have two new U9-226 O-Rings (Part #13) to replace the old O-rings if necessary.

I am not 100% that the thread is 2" NPT, so verify as needed.
 

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I don’t believe those are 2” MPT, they are more than likely 2” straight threads. They don’t have a taper. Typically you use an o-ring with straight threads and pipe tape/sealant with tapered threads.
 
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The difference between a straight thread and a tapered thread is minor and the threads are the same except for a taper.

For the purpose, a regular PVC fitting will screw in.

You can use some Teflon tape to make the seal for the descaling.

NPT is defined by ANSI/ASME standard B1.20.1.

The taper rate for all NPT threads is 1 inch of diameter in 16 inches of length (3⁄4 inch per foot or 62.5 millimeters per meter) measured by the change of diameter (of the pipe thread) over distance of thread.

American National Standard Pipe Thread standards, often called national pipe thread standards for short, are United States national technical standards for screw threads used on threaded pipes and pipe fittings.

They include both tapered and straight thread series for various purposes, including rigidity, pressure-tight sealing, or both.

The types are named with a full name and an abbreviation, such as NPT, NPS, NPTF, or NPSC.

MIP is an abbreviation for male iron pipe, and FIP is an abbreviation for female iron pipe.

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I will pick up some threaded 2" PVC fittings and give it a try. Even if it is not a perfect seal, as long as I can get the descaling solution to circulate, I'll be happy. I'll report back with my findings, but it may be a few days before I can get to it. Thanks for the help.
 
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I was planning on just using a gallon of vinegar as that is what was suggested for my tank-less water heaters. Would that be advisable?
 
There are several different types of descaling solution available.

Try to find one listed as safe for copper.

Citric acid is one type of descaling solution.

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www.homedepot.com

Hercules Haymaker Tankless Water Heater Descaler 35230 - The Home Depot

Hercules Haymaker Tankless Water Heater Descaler quickly and easily dissolves inorganic deposits that restrict flow to restore circulation and heat transfer efficiency. It's safe for potable water systems
www.homedepot.com
 

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