Home>Discussions>PLUMBING>Water Heater Temp/pressure valve leak
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JLMCDANIEL
Re: Water Heater Temp/pressure valve leak
MSSP wrote:

Jack I have read many of your posts and realize you have a lot of knowledge with your age. The OP said it leaked before and it still leaks. NashuaTech stated most hot systems dont need an expansion tank and most increase in pressure is absorbed by the piping and air in top of heater. I want to know what brand of water heater holds air in the top. I have installed sevral hundred water heaters in my 26 yr plumbing career and have never seen any w/h hold air in top for pressure expansion. Most new water systems have a check valve or a PRV with a check valve and dosent allow back feed into water main, Thus the reaason alot of people need an expansion tank.

As far as dobbs stating "it is just sloppy troubleshooting procedure to shoot off my mouth and insist on additional componants and exspense" And for the new boiler comment that seems like a very mature statement to me. I live in the mid west and op lives in Mass. I was not trying to sell just trying to help
An expansion tank is pretty inexspensive to install yourself. Seems pretty handy for doing what he/she has done already.
To the Gator12, 140 water is pretty high. it can cause third degree burns in about 5 seconds. I hope you find out why the T&P keeps leaking.

The PRV will leak if the temp or pressure is exceeded.
While all WH's have jackets that are flat on top the tank them selves are domed. The cold water feeds into the bottom via the fill tube, the outlet is located on the low side of the dome so there is always a small cap of air in the dome, it is designed that way to handle expansion of the water under normal and recomended use and to help prevent over pressure. Over heating can cause a pressure that exceeds normal operating conditions. NashuaTech's information was correct. Reducing the temp would be the first option to try. An expansion tank should not be needed if the WH is operated within its recommended settings.

You are right, Dodds did seem to throw a tantrum rather than just suppling information.
Jack

MSSP
Re: Water Heater Temp/pressure valve leak
JLMCDANIEL wrote:

The PRV will leak if the temp or pressure is exceeded.
While all WH's have jackets that are flat on top the tank them selves are domed. The cold water feeds into the bottom via the fill tube, the outlet is located on the low side of the dome so there is always a small cap of air in the dome, it is designed that way to handle expansion of the water under normal and recomended use and to help prevent over pressure. Over heating can cause a pressure that exceeds normal operating conditions. NashuaTech's information was correct. Reducing the temp would be the first option to try. An expansion tank should not be needed if the WH is operated within its recommended settings.

You are right, Dodds did seem to throw a tantrum rather than just suppling information.
Jack

JLM I respect your thoughts on this issue. But this is where we agree to disagree. Can you please show me a diagram or a maufacure's spec on a w/h holding air for the purpose of expansion.

johnjh2o
Re: Water Heater Temp/pressure valve leak

There is no dome on the water heater. We are talking about as gas water heater, they have a center flue. Even if there was, most heaters have the T&P valve on the top of the heater and if his valve is leaking would it not expel the air in the top of the heater? I also believe in his state thermal expansion tanks are required by code. Bottom line he need a tank.

John

JLMCDANIEL
Re: Water Heater Temp/pressure valve leak
MSSP wrote:

JLM I respect your thoughts on this issue. But this is where we agree to disagree. Can you please show me a diagram or a maufacure's spec on a w/h holding air for the purpose of expansion.

My apologies,I didn't edit my post very well. It was suppose to say " I believe it is designed that way to handle expansion ". I have disassembled several water heaters to cut and use the tanks for other purposes, all had domed tops and outlets and PRV connection below the high part of the dome. It would be impossible to fill those units all the way to the top.
Jack

johnjh2o
Re: Water Heater Temp/pressure valve leak

Jack a PRV is a pressure reducing valve. The most common use is on the water main, to reduce the pressure if it is to high. They have a built in check valve. When a PRV is installed it will not allow the thermal expansion to go into the city main. That is reason for the expansion tank. I think you are confusing a PRV valve with a T&P valve.

John

JLMCDANIEL
Re: Water Heater Temp/pressure valve leak

Sorry, I have always heard the units on the WH referred to a pressure release valves.

Jack

Rosaleeta
Re: Water Heater Temp/pressure valve leak

Wow, you guys should hear yourselves, clucking away like a bunch of old hens!

JL Mcdanial is the only one providing spot on clarity on this thread.

He's to be congratulated as he approaches 5000 posts on this forum.

MSSP
Re: Water Heater Temp/pressure valve leak
Rosaleeta wrote:

Wow, you guys should hear yourselves, clucking away like a bunch of old hens!

JL Mcdanial is the only one providing spot on clarity on this thread.

He's to be congratulated as he approaches 5000 posts on this forum.

I am not clucking like a hen I am just stating actual facts. A water heater does not hold air for expansion. I am not trying to start an argument. I am jsut stating facts. I think we all agree to disagree. i was jsut asking JLM to show proof or a brand and model of a heater that holds air in the top for expansion. I have never heard of one. That is all

Joe
Re: Water Heater Temp/pressure valve leak

hello,

I apologize for the delay in getting back here.
The water temperature coming out of the faucet is 110 degrees in the first floor kitchen. This faucet is just above the water heater. I had someone come in to check the pressure at my slop sink in the basement and he said it was 75 psi. He also noted a some sort of pressure reducing device where the water enters the house.

The water heater has been leaking from the day i bought the house which was about two years ago. When I noticed the leak from the TPR valve I looked at the water heater more closely. I noticed the previous owner left a TPR valve on top of the water heater. It looked new, so I installed it. The leak didn't stop. I went to the local supply store and bought a new valve which I installed and sitll leaks to this day. All have been rated at 210 degrees and 150 psi. I think I'm way below these settings.

Joe
Re: Water Heater Temp/pressure valve leak

Here is some additional information:
The temperature and pressure relief valve is a:
WATTS blue ribbon model No.100XL

The valve only leaks when we use hot water or the water needs to be heated. When the water heater is sitting idle (not making any noise) the leaking doesn't happen.

I am not sure if I have any type of backflow prevention device at my house, but it would seem to make sense if I did.

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