I have the desire to replace the T & P valve on my 19 year old water heater, but a close inspection reveals potential difficulties. The original installer used the green tinted paste (specifically for natural gas lines) for all of the threaded connections. The problem is, unlike standard pipe dope with PTFE, this stuff hardens to the consistency of concrete. I was wondering if it might make sense to fasten on a pipe wrench and tap the end with a small 3 pound hand sledge to shock it loose the way an impact drill does. The valve is screwed into a bushing—the tank is 75 gallons and has one inch fittings on the inlet and outlet up top, although I’m not certain if this is a 1” to 3/4” reducer or just an extender bushing. But given that it has a hex, would it be advisable to use an impact drill and socket to remove this part as opposed to a long pipe wrench? I know that water heaters have some delicate components, i.e. thermocouple, igniter, glass lining and was wondering if the vibrations from either an impact drill or banging on a wrench end could cause enough vibration to damage internal components. If anyone has successfully employed these methods to remove stubborn fittings, please let me know. Thanks a bunch.
Hi, I’d start with a non-impact approach to prevent possible tank damage. If the steel pipe can be unscrewed from the relief valve, good. I’d use two good-sized wrenches… maybe 18 inch, one to turn the pipe and one to put on the relief valve so it doesn’t twist sideways. If that doesn’t move things, you can heat the connection first with a torch and try it again. Next, I’d put a steel plug in the relief valve so the end doesn’t collapse and use one of the 18 inch wrenches on it to see if it will move. If not, put a two foot (or so) cheater on the wrench. That will give you enough force to break off the valve, which you don’t want to do. but if it happens, than a socket on the bushing is your next step. I’d put thing back together with teflon tape so you never have to do this again!