Water heater PRV keeps going off... not leaking

[cjz7945]

The pressure relief valve on our water heater keeps going off and venting hot water to the floor. This happens most times during the night when there is no water usage. I guess it’s good that the pressure relief valve is working and doing its job, but the bigger concern is why…?

We had recently replaced the house pressure regulator & backflow valve on the incoming service from the street. The pressure regulator sets the house pressure at 55#. I replaced the expansion tank on the cold line near the water heater and set its pressure at 55#.

Would this be a bad thermostat-thermocouple on the water heater… heating the water too hot thus activating the pressure relief valve?
The temperature setting on the water heater is at the notch setting on the dial… I think this is 120F.
Not the MAX but not the MIN either.

Thanks.

 

[havasu]

You have a potentially dangerous situation. It may just be a faulty TPR valve, or you are accumulating dangerous pressure. Either way, you need to call in the experts who can help you from a disastrous situation.

 

[jeffmattero76]

I agree that this could potentially be dangerous.

I would suggest using a thermometer a the hot water faucet that is closest to the water heater, to determine if the thermostat on the heater is not functioning properly. The temperature of the water after running for a few minutes should be around 120 degrees.