Water heater tp valve

I went on a service call today where the lady said her gas water heater tp valve would open up occasionly and let water out (at least once per day). She has her temp set fairley low. Of course it didn't do it while I was there. The house is in a new area where the water preasure might be high until more homes are built? My experience in the past is they either leak all the time or not at all on a gas water heater. What do I need to look for or test?
Thanks,
AzCraig
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BTW--The water heater is three years old and there is no pressure regulator on the home.
AzCraig

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cm wrote:

You'll have to put a pressure gauge on the drain cock to see what's going on. It may be that service pressure goes way up at off-hours.
My guess is you will need to install a pressure reducing valve AND a thermal expansion tank.
http://www.flexconind.com/html/wh-series_.html
Jim
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Speedy Jim wrote:

I have a relatively new (1 yr old) Gas water heater, and it does the same thing. The old one NEVER did it, and nothing has changed about the plumbing... and I don't have the water as hot as it was in the old one. It was take out the old one, and put in the new one. I believe I have a defective relief valve... but haven't taken the time to replace it. It usually flows a little after I have used the Hot water for a while. I tried to get the folks back who installed it like a month later, but they had gone out of business <sigh>
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1. Test the water pressure if below 70 PSI then you don't need a regulator.
2. Replace the T&P valve either stay with the std 150 deg or look at the 175 deg
3. Expansion chamber is a next step.. make sure you have a backflow device on the water line coming to the house.
Randy
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