Water Heaters - TPR valve hookup - confusing

I need to replace my water heater and I'm not sure of the hookups on my TPR valve. When I bought the home, I noticed in the inspection that the TPR valve did not route anywhere externally (my water heater is in the middle of my house in a closet) so I wanted it addressed and these pictures show what they did.

http://www.flickr.com/photos/9508542@N06/

I'm not sure what would actually happen in the event that there was a high pressure situation, but it looks to me like the pressue would release back into the gas line?

Any help figuring this out would be appreciated.

Thanks, Shawn

I have never seen anything like that in my almost 20 years experience. :eek: Don't get me wrong, I've seen some creative things but.... wow. I cant figure what the purpose of that setup is.

If that T&P valve goes off, the pressure has no where to go! On top of that it will ruin your gas control valve on the water heater. They are not meant to have water flowing through it.

What you need to do is replace that contraption on the water heater with a T&P similar to what you have outside. National standard say it's has to be piped to 6 inches to the ground but local code with vary. If it needs to be piped outside, the pipe can not run upwards at all and can not restrict the flow in any way. Then the gas line only needs to go from where the shut off valve is to the gas control valve on the water heater.

Thanks for the reply. Supposedly, he installed that TPR outside when he did this. It was supposed to be the way the water would release externally in case of an incident. I wondered if this would work by forcing the water back through the water line and then it would release outside at that TPR.

Does this setup look like it will be pretty easy to replace with a new Water Heater? I thought that all of the connections look pretty good and that I wouldn't have to redo any piping. (besides fixing that TPR fiasco).

What you have in the side of the water heater is a specialized TPR valve that shuts off the gas to the burner (notice the gas line attached to it?) when the TPR trips. The gas and water never mix; the tripping of the TPR just shuts the gas flow off. This is an added safety; instead of just venting water to the interior of the house, it shuts off the energy source (the natural gas or LP) to the WH burner itself. Nifty.

This link shows the type of valve in the side of your WH:
http://www.watts.com/pro/_productsFull_tree.asp?catId=64&parCat=290&pid=3435&ref=2

The external TPR valve is just in the system to dump excess system pressure, like the P portion of a TPR valve normally would. I don't see any problem with it being placed elsewhere, especially since your WH is inside the living area, but you might check with the inspection people in your jurisdiction for the proper location of the external TPR.

So if I follow correctly, the pressue buildup that would normally exit through the TPR on the side of the WH, would actually exit through the TPR valve outside? That would be good.

So it looks like I should hook this backup the way it is with the new WH. Correct?

Thanks, Shawn

Not to worry. The device on the side of the water heater is a Watts 210 high temp gas shut off. If the TEMP gets too high ( 212º) it shuts off the gas. It does not do anything about pressure, so you are also required to have a PRESSURE relief valve outside the house, as you show in the picture.

I usually install these using some black pipe, and elbows, to use shorter flex lines and a little neater appearance, but code wise, you look OK.

These are commonly used in your situation, where the location of the WH makes it inconvenient to pipe the discharge from a conventional TP outside.


By the way, I always insist on a NEW Watts 210 with a new water heater. They don't last forever. Unfortunately, they are over $100!

Oh, thank you formula and 594. I stand corrected on my last post. Those gas safeties aren't used around here or if they are they are far from common.

Thanks.