life of a T&P valve?

[Nate Nagel]

Hi all,

yesterday I did the annual flush of my gas fired water heater - and at the same time I "burped" the T&P valve, as is my habit. It's on the side of the tank near the top, and there's just a straight length of copper pointing toward the floor coming out of it. I usually leave a small plastic container under it to catch any drips so I can see if there's a situation developing. It was replaced two years ago after it got weak, popped off in normal operation (pressure surge?) and then didn't seal properly and kept dripping over a long weekend while I was out of town. D'oh!

Anyway, I just looked in the container and there were a couple drops of water in there, so I "burped" it again. I put my pressure gauge on the drain and it is reading 70 PSI same as it did last time I checked.

I assume that these things have a finite life, but two years (literally, less than 25 months) seems a bit short...

Is there anything that commonly kills these, or did I just get a bum one? It's a Watts brand one, FWIW, whatever is sold at the Orange-Colored Store and the same model number as the one that was on there before.

I'll keep an eye on it to see if there was just a rogue piece of debris in there and all is well now, but I've been keeping the tank well flushed, so I can't imagine there's that much...

Now I'm thinking I really should plumb the T&P to dump into the deep sink since I've already had issues with it once before (no floor drain in laundry room, of course...)

nate

[Tony Hwang]

Hmmm, It could be a case of wrong T&P valve or running water way too hot.

70psi is little higher than normal incoming water pressure. Think hot water tank pressure in normal working state is lot higher than 70psi.

[Joe]

Consider installing an expansion tank and reducing the water pressure to a more normal 50 PSI. That should give you a decade or more of service from your pressure relief valve.

Joe

[hallerb]

in hard water areas, dripping after moving is normal. expansion tank is meaningless unless main water inlet has backflow preventer.

my approach, leave tank ALONE, dont mess with it at all, till it leaks, or reaches 9 or 10 years old, then replace at MY convenience, rather than waiting for a leak at a inconvenient time

[Bob F]

My water pressure is always 70psi, as supplied by the city. My water heater is also always 70psi.

The only reason the water heater would get higher than the supply is if you have a check valve before it or on the supply water input. (Which could be a regulator)

[Bob]

is if you have

Water expands as it heats. That's why the T&P valve is there! If that valve doesn't open and the heat control malfunctions, your water heater could turn into a missile. Mythbusters proved that.

[Nate Nagel]

Only if you have a check valve in your system, otherwise the water just expands into the city main.

nate

[Nate Nagel]

I hear ya, but my water is not particularly hard, and if I replaced the whole water heater every two years that could get expensive!

Hell, I'm almost lazy enough to not bother to flush it, I am definitely too lazy to want to replace something simple like a T&P valve that often... even if they are only $13 or whatever I paid for the last one

nate

[Nate Nagel]

It's the same model as what was there before, which I assume came with the water heater. I do have it set a little hot because there's only two adults in the house and I like hot showers and clean dishes, but still, probably 130-135F not 200 or whatever it's supposed to pop off at... pressure gauge has been on a full day telltale at 85 PSI (probably from shutting off faucets) and there was another small puddle in the container when I got home from work :(

nate

[Phisherman]

I don't ever touch the T&P valve, not sure why this would be necessary at all. The only maintenance is a yearly flush. But the expansion tank seems to improve the plumbing pressure variances.