Regulators instead of expansion tanks on water heaters



I have been seeing these regulators replace expansion tanks in newer homes but never with a drain pipe. Additionally, there’s no drain pipe on the TPRV. Is this right?
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Are you sure that’s not a thermal expansion valve? It looks like a adjustable relief valve.

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Jason, where are you located? How old is the home? This is helpful.

GA follows 2018 IPC, which states the following:
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So a tank or device shall be installed…but be sure to see when they are needed and if you were able to confirm this requirement. Go gently into the abyss.

TPRV drain pipe. I have never seen the drain pipe “not be required” along with many other drain pipe requirements.

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https://www.watts.com/resources/references-tools/thermal-expansion

I do believe the calibrated pressure relief valve may be used. If this is in fact what has been installed in the OP’s photograph I do believe it is correct.

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Right, tank or device is the way I understand it and was the intention of my post. I believe many inspectors are looking for tanks only and miss the device which gets them in trouble.

Furthermore, in my state tanks/devices are required on closed systems, which is nearly impossible to verify.

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I agree I see a lot of thermal expansion valves but I have never seen a calibrated pressure relief valve. This forum can have some valuable information.

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New construction I am seeing more and more of this; relief device connected to the TPRV drain pipe. I see no accommodation for this anywhere in code. Must be a local thing or just wrong. I mark it as wrong.

I see this quite a bit too. I call out the tee that has been installed in the pressure relief valve discharge piping and ask that the thermal expansion valve be ran separate.

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I was going to question that Tee fitting in Brian’s pic. But you pointed it out…

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Thomas sometimes this forum has some good stuff.

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Not only good stuff, but some great inspectors to learn from…inspection wise… :stuck_out_tongue: :shushing_face: :wink:

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You teamed up with a really good one a few weeks ago.

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Yes, looks like an adjustable pressure relief, probably for the whole house. I see those on all new builds here, typically at the exterior, but occasionally on the water heater.

Correct me if I am wrong, but I think they are required on hybrid water heaters. (this one isnt, obviously)

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I don’t think so!

I guess you are right. I had to research it, because every time I see a hybrid heater, it has a pressure reducing valve installed. (not a pressure relief, like I mentioned)
At least according to AO smith, it is RECOMMENDED to have either an expansion tank, or a pressure reducing valve set to 50-60 psi.
208V NEEA Updates.indd (ferguson.com)

Good discussion here!

Recently in my area, a builder has begun putting an expansion valve on the cold side discharging into a standpipe, with the TPRV discharging via a separate line into the same standpipe. I had to triple check the code book when I first saw it. Builder prefers it and they make a great home so I won’t argue!

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Daniel I see no problem with the TPRV pipe dumping into a standpipe separate from the thermal expansion device. Is this what you’re jurisdiction is allowing?

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Correct, no issues. Just different since we usually see expansion tanks in use.

No, they are separate lines. I was just referring to heat pump water heaters having a separate pressure relief valve.
This is on my own home. This hybrid heater actually has a whole home pressure relief valve, and a vacuum relief valve, as well as the TPRV.

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