IGot2P wrote:

Okay, it is a two to three year old electric water heater and this
evening the relief valve tripped and dumped a limited amount of water. I
have no clue as to why it tripped, it never has before. The down pipe
from the relief valve is still dripping even thought I have opened and
closed the valve several times.

1.) I know that the relief valve is both pressure and temperature
sensitive but what is your best guess of why it tripped in the first place?
2.) Is it the nature of these relief valves to not totally re-seat once
they have tripped?

It didn't do any damage for three reasons. First, it let out a limited
amount of water. Secondly, the down pipe is very close to a floor drain.
And finally, we have a water alarm near that floor drain and it went off
and we just happened to be home.

Unless most all of you think that something is messed up with the water
heater I plan to just replace the relief valve in the morning and let it
go at that. Although I never do, I just might shut it off when we leave
for warmer weather this winter.

Happy Holidays,

Don

What is your water source, "city" water? Do you have an expansion tank
in the system to account for expansion of water as it heats? City water
supplies normally have backflow check valves, so when the water heats
the pressure rises if there is no expansion tank.

If the starting water pressure was a little higher than normal, you used
a lot of hot water so there was more cold water being heated and thus
expanding, a leaking backflow valve was replaced, etc. the pressure
could spike above the trip point of the relief valve.

Relief valves tend to be one-shot things, once they trip they rarely
reseat properly or they get some crud in them and they tend to drip
forever after. Replacing the valve will fix the ongoing drip, but if you
don't fix the underlying problem it will just repeat.