: I am just about to replace my pressure relief valve on the hot water tank. Over thanksgiving the thing started dripping (just like the PRV before it) and continued to drip once I tested it (a two second release of the valve).

: Because I replaced this thing a year and a half ago I wonder if there are other checks on the tank that I need to make. I know the town typically has very high mains pressure.

: I notice some talk about expansion tanks that may be necessary if I have a 'closed system'. How do I know if I have a closed system? Also, can you recommend other checks of the hot water heater that I need to make?

: thanks!

Reply:
You have a closed system if you have a pressure regulating valve without an internal bypass on the water main or if there are any check valves installed (depending on location) on any distribution H or C water lines.
Normal water pressure is 50 - 75 lbs. In excess of 80 lbs., a PRV is required.
The type of WH that you have will determine what, if anything needs to be checked.
The Water Dept. will check your water pressure (for free) and let you know if you need a PRV.
Good Luck. e-plumber