I just finished replacing the pressure relief valve on my Rinnai hot water heater. Everything went well, I turned on the cold input and wham, water just started gushing out of the relief valve. All the specs line up on the valves (150 PSI), in fact the new one has a higher BTU/HR rating by a long shot (500,000 old vs 934,000 new).
I have to ask now. Could I have done something wrong during installation? It was all so obvious what to do, teflon tape, screw the valve into the hole, put the drain pipe on the bottom and done.
After inspection of the new valve it appears that the inner gasket had come unseated therefore not letting the valve close. I assumed it was defective, so I exchanged it for a new one, the gasket looked good.
The replacement had a seated gasket, I opened and closed it manually and it seated nicely. I installed, same as before, as soon as I put some water pressure to it, it just started gushing and wouldn't closed. When I removed the 2nd new one, the same thing happened with gasket, it unseated and pinched in the valve.
Now, I know I installed it right, I know it's the "correct" valve, I had them double check in the catalog and specs for our Rinnai:
Could the catalog be completely wrong? Could it be possible that 2 valves were defective? It's the only "Pressure Only" valve we could find in town. The rest are all "Temperature and Pressure" with the thermal probe that won't fit in our heater.
Separate question: can you use a T & P valve be removing the probe and have it still work?
The old valve still holds pressure for the most part, it just trickles/drips water out (which is why I'm replacing it)