Hi. I am installing a pressure relief valve on a mastertemp 125 heater as it has failed plumbing inspection for the lack of the relief valve. Do I simply thread in pipe into manifold? Not certain how water comes out of manifold to relief valve. Thanks
Pressure relief valve installation
- Thread starter mikeyez72
- Start date
Welcome! 
It's part 13 on page 52 of https://www.pentairpool.com/~/media/websites/pool/downloads/heaters%20and%20heat%20pumps/manuals/mastertemp_125_high_performance_heater_installation_and_users_guide_english.pdf
Go look at your household hot water heater. You'll see one there, too, usually up near the top with a discharge pipe leading down to the floor or out through the wall somewhere.
There's probably a plug in the manifold that you need to unscrew to thread the valve/pipes in. Possibly it's a threaded blind hole that needs to have the bottom drilled out. Then it's just a matter of teflon tape and pipe wrenches.
It's part 13 on page 52 of https://www.pentairpool.com/~/media/websites/pool/downloads/heaters%20and%20heat%20pumps/manuals/mastertemp_125_high_performance_heater_installation_and_users_guide_english.pdf
Go look at your household hot water heater. You'll see one there, too, usually up near the top with a discharge pipe leading down to the floor or out through the wall somewhere.
There's probably a plug in the manifold that you need to unscrew to thread the valve/pipes in. Possibly it's a threaded blind hole that needs to have the bottom drilled out. Then it's just a matter of teflon tape and pipe wrenches.
Thanks richard. I do have all piping and tape required, there is no plug in manifold. I am attaching a picture of what is in the threaded hole in manifold.
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My thought was that if I thread in pipe, it will open up. But I am uncertain and not looking to strip the plastic threads
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My thought was that if I thread in pipe, it will open up. But I am uncertain and not looking to strip the plastic threads
Attachments
I can't tell from the picture - are there threads in the hole?
And before you attack it with any tools, you might want to wait for someone in the industry to see this and respond.
And before you attack it with any tools, you might want to wait for someone in the industry to see this and respond.
On Pentair Mastertemp heaters other than the 125 there is a plug on the left side of manifold to install. I cannot find any info on the valve install on the 125, but the previous model the Pentair NT you have almost the same manifold setup and on that one you need to drill a 3/8" hole through the bottom. But you must remove the flow control first. maybe someone who has installed this heater will chime in. Also I found the kit for the relief valve but it's outrageously priced. https://www.amazon.com/Pentair-460925-Pressure-Connection-Replacement/dp/B008H273ZS/ref=pd_lpo_sbs_86_t_0?_encoding=UTF8&psc=1&refRID=237NBJK2PADPMACFB315
Thanks kadavis, I haven't been able to find info anywhere on this. I called there customer support Friday and gave up after being on hold 40 minutes. They have been closed since, will try again tomorrow and will post theor instructions
A picture of the entire manifold would be best but yes this is the spot for the relief valve. On these units they want you to drill out the spot and then add the piping and valve. It is surprising they don't talk about it in the manual from what I have seen. Once you have it drilled out, pump turn off when you do this, then I would use what your local code requires for pipe and then add the relief valve. I use 3/4 galvanized pipe. Then from the valve I run a section of pipe down towards the ground or per the requirements of your local code. Yes you thread sealant on the pipe.
The inspector will come by and flip the lever on it to check that you drilled out the hole and water flows. In fact they say to test the valve every so often for functionality.
