Thread: hot side pressure relief valves

Howdy all,
Been following a while but this is my first time posting.
My plumbing guru tells me that the pressure relief valves installed on plumbing systems after the installation of a Watts 210 on the water heater are now required to be installed on the hot side only. I have no reason to disbelieve what he says... My question is this: Are you inspectors calling pressure relief valves installed on the cold side (as was commonly done, usually on an exterior faucet) a repair item..., or deficiency, as they are having us refer to them now in Texas?
Jaime Fushille
El Paso

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Originally Posted by Jaime Fushille

Howdy all,
Been following a while but this is my first time posting.
My plumbing guru tells me that the pressure relief valves installed on plumbing systems after the installation of a Watts 210 on the water heater are now required to be installed on the hot side only. I have no reason to disbelieve what he says... My question is this: Are you inspectors calling pressure relief valves installed on the cold side (as was commonly done, usually on an exterior faucet) a repair item..., or deficiency, as they are having us refer to them now in Texas?
Jaime Fushille
El Paso

I had to reread this post a couple of times to figure out what you are asking The pressure relief valve will either be on the tank or on the hot side. It would not do any good for it to be on the cold side.

Now if you are talking about a pressure reducing valve, this is always on the cold side so that the water supply pressure is reduced before it gets to the house.

Hi Scott,
Thanks for the reply.
I don't know about AZ, but out here, after the installation of a Watts 210 gas cut-off valve at the water heater, it has been common practice for several years to install a pressure relief valve on an exterior faucet. Watts 210's are frequently retrofitted if, for whatever reason, the T/P relief valve or its drain line are not in compliance with current code (reduced from the output dimension or run in an upward direction, etc.).

The gas cut-off valve eliminates the danger of over-pressure conditions at the water heater, but high pressure can also result from other conditions such as a damaged or poorly adjusted pressure regulator. Hence, the requirement for a pressure relief valve somewhere else on the plumbing system. Because a high pressure surge from a damaged pressure regulator doesn't only affect the hot side, it was considered acceptable to install the T/P valve on the cold side, usually at an exterior faucet. Now that it is no longer acceptable, I've run into a bunch of the old "cold-side" T/P valves and the question I had was: Are inspectors calling that a repair item...? It has not yet appeared in the Texas Real Estate Commission Standards of Practice, so I was just wondering what the inspectors of the world are doing about it.
Jaime Fushille

Staight from the Watts site.
DO NOT INSTALL ON THE COLD WATER LINE

Welcome to the forum.

Here is the pdf installation instructions.

http://www.watts.com/pdf/IS-210-5.pdf

By the way..a Watts pressure relief valve is different than a regular relief valve. A "normal" relief valve can be installed anywhere within the system, cold or hot. Being is it only determines if there is excess pressure.

Originally Posted by Jaime Fushille

Hi Scott,
Thanks for the reply.
I don't know about AZ, but out here, after the installation of a Watts 210 gas cut-off valve at the water heater, it has been common practice for several years to install a pressure relief valve on an exterior faucet. Watts 210's are frequently retrofitted if, for whatever reason, the T/P relief valve or its drain line are not in compliance with current code (reduced from the output dimension or run in an upward direction, etc.).

The gas cut-off valve eliminates the danger of over-pressure conditions at the water heater, but high pressure can also result from other conditions such as a damaged or poorly adjusted pressure regulator. Hence, the requirement for a pressure relief valve somewhere else on the plumbing system. Because a high pressure surge from a damaged pressure regulator doesn't only affect the hot side, it was considered acceptable to install the T/P valve on the cold side, usually at an exterior faucet. Now that it is no longer acceptable, I've run into a bunch of the old "cold-side" T/P valves and the question I had was: Are inspectors calling that a repair item...? It has not yet appeared in the Texas Real Estate Commission Standards of Practice, so I was just wondering what the inspectors of the world are doing about it.
Jaime Fushille

Hi Jamie,

Again, the T/P valve requires temperature and pressure to activate. So putting it on the Cold side will not do anything. I would give Watts a call, they are very helpful with questions like this. Also on their site, you will find all types of installation guidelines. They have extensive install instructions for the 210-5 valve along with diagrams, and nothing is said about a T/P valve on the cold side.

Scott, two different animals. T&P vs pressure relief. 99% of the installations include the temperature and relief valve but I have seen relief valves only, which may be installed anywhere in the system.

The Watts looks like it has to be installed so that the probe is in the tank.

Originally Posted by Wayne Carlisle

Scott, two different animals. T&P vs pressure relief. 99% of the installations include the temperature and relief valve but I have seen relief valves only, which may be installed anywhere in the system.

The Watts looks like it has to be installed so that the probe is in the tank.

I think that Jamie might have the two terms confused, I have a pressure relief valve on my home and this is what I have started seeing more of instead of an expansion tank. The TPR valve needs to be at the water tank, as does the 210-5 valve.