Hi, I'm new to the forums here. I have an ancient Anthony Citadel III LP pool heater and the relief valve has been leaking. I'd like to replace it, but I'm not sure exactly what valve to get. There is a tag on the existing valve but it is hard to read. The main thing I'm unable to read for sure is the pressure rating. It is a Zurn P1000A 200000 BTU/Hr rating, but the pressure rating I can only read the last two digits of 50 (psi). It might be just 50 psi or it might be 150 psi (there are scratches on the tag). I've found a matching Zurn model on the internet with the same BTU rating that comes in various pressure ratings, but not 50 psi, though it does have 150 psi. On a plaque on the inside of the heater it says "working pressure 50 psi" and "hydro test 150 psi" just to make things more confusing. Anybody have any thoughts on the right valve or what the consequences would be of getting the wrong valve? Thanks for reading.