Pressure Relief Valve discharging

[r16s]

Ok - I have read all the archived posts on water heater pressure relief valves leaking but haven't quite seen my scenario. Basically, I replaced a 50 gal propane water heater with a new 50 gal propane water heater of the same brand but newer model with a pizzo igniter. Ever since I replaced it the pressure relief valve has been discharging anytime a faucet/toilet is opened then shut. This did not happen on the old water heater. I did not install the heat trap nipples (mainly because the old one (3 years old) didn't have them.) I do not have an expansion tank nor do I have a PRV. I have not checked the water pressure yet but am on public water. Any ideas? My first thought is to check the pressure but then what? Thanks! - Rick

[Ejbogusch]

Rick it sounds like you have a condition called water hammering. Simply this is when a valve rapidly opens and closes. This condition can make your T&P valve release. I would first make sure your water pressure does not exceed 75-80 psi. If it does replace your house regulator.

Second, make sure your toilet float is not rapidly opening and closing its valve when it gets near the top. If so replace it.

If all else fails you can install an expansion tank which should fix the problem.