Water heater relief valve leaking...a lot.

[Kitch]

The valve on the water heater has started to leak/flow. Every time someone takes a shower, washes clothes using hot water, or runs the dishwasher it flows from the overflow pipe for 15-20 minutes. Obviously when refilling/reheating. Everything else works just fine. Can I just replace the valve, or is a new water heater recommended?

Thanks,
Kitch

[jadnashua]

While it could be a weak spring in the T&P valve, there is another common problem. You might need to install an expansion tank. If you have a closed system (some water meters have a check valve, or you could have a check valve, or a pressure reduction valve), after using some hot water, the cold water expands as heated it expands raising the pressure. The safety valve leaks out the water until the pressure is reduced.

[Cass]

You most likly need to install an expansion tank. The water pressure needs to be checked first. After the pressure gauge is put on turn the cold water on at any faucet for 30 seconds then shut it off and read the gauge.

[MikeG]

Kitch -

I had the same issue a week or two ago. I replaced the 20 year old PRV, 1 year old T&P on the heater and added a Watts expansion tank. The problem was solved with the expansion tank. I replaced the PRV since the pressure was fluctuating and running high. The T&P runs about $8 at HD or any supply shop so you might as well replace that first and then decide on the expansion tank. The Watts tank runs about $40 at HD so you can do everything for under $60 in parts including fittings.

Mike