Our water heater always has a web spot under it. It looks like the expansion valve is routinely releasing water. Is this normal? Our old heater didn’t have this problem to the same extent.
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It could be a defective T&P valve, or even a bad water heater thermostat, but most likely the problem is due to having a check valve or pressure reducing valve where your cold water enters the house. When the water in the WH expands as it heats, there's no place for it to go except out the T&P valve.
The solution is to install an expansion tank on the cold water line. This is a small 1-2 gallon pressure tank that acts as a "shock absorber". There are versions that can be installed with a "vampire" (self-piercing) fitting, if you don't want to plumb one in.
Be sure to observe the tank instructions re distance from the heater. Too close and hot water can back up into the tank and shorten its life.
Thanks, Dan/Boss...I'll look into that!
or just turn the temperure down some
It's pretty low as it is (we have a 2-year old in the house). The old heater didn't have this problem to the same extent, even though it was hotter (though it was a bigger heater).
ARGGH.
Well, spent an hour this afternoon replacing the pressure release valve. Re-filled the heater. So far so good. Fired her up and then checked on her a few minutes later...dripping more than before. Ugh.
It sounds like I need this expansion tank. Is this a DIY project, or should I just get a plumber out here to figure it out? Is this a Home Despot product or do I need to go to a plumbing supplier?
What bugs me is that this just started recently. The heater is new (1 1/2 years) and was just fine until recently.
Did you read my little note on the pressure test first? It's important to get the right sequence or you'll just keep replacing stuff till you find the problem. Some time if there has been water line replacement or upgrade you'll get the higher pressures. You could call the city and check if any work has been done in the area lately.
If you want to run the drip to a drain you can easily sweat a male hose to the copper and run to drain with garden hose. Only temp till you figure out why.
By the way, this seems like a good post to mention that you should NOT test the TP valves; often, well-intentioned people like to lift the levers to test the valves; most TP valves are cheap, and will weep forever after you "test" them.
From my understanding, those T and P relief valves are a one shot deal..once ya open it, it's shot.
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Boy it looks like this thread has been written by some of the HD "experts".
A P&T safety is not a one shot deal like a fuse. BUT, on the other hand they are not designed for everyday usage either.
So it is not uncommon for them to continue to leak after they have once opened. *SOMETIMES* you can manually open then and flush out any dirt it is in the seal, but don't bet the farm on it.
Now just because there is a house "up the hill" does not mean that the pressure is too high. Is that hill 5ft high or 5000 ft high. Who say that they have adequate pressure. Their pressure might be so low that it takes them an hour to fill the tub.
Just increasing the size of the city supply line does not increase the static (the pressure when no water is running such as at night). But that could be parts of other system upgrades such as new storage tanks, new interconnect lines, new high service pumps, etc that could have increased the pressure.
In fact if you are near the high service pumps and larger pipign was installed you maximum pressure might have gone down. We have a couple of tankless systems that uses multiple staged/varriable speed pumps that are controlled by the flow rates and system demand curves to maintain usable pressures at the far end of the system. So when flow rates increase the pump staging is increased to overcome the losses in the system and the pressures near the pumps will increase.
But if a pressure regulator is installed, or if the city has installed backflow devices or checkvalves, the system (your tank) is now a closed system. And if you have lots of cold water in the tank and it starts to heat up the water expands and the pressure increases until the P&T bleeds some off. An expansion tank is them needed.
As far as a one-shot deal goes, I wouldn't go that far, but it's not a good idea to "test" them; they are frequently hard to make reseat fully. That information, by the way, comes not from personal experience, but from a factory training session of the plant when I was in the safety/release valve business. We were doing industrial valves, but the conversation changed to residential TP valves one day. One guy tested his TP valve every 6 months, just like a good industrial boiler operator would.....he complained that his valves never lasted.
The main danger with "testing" the valves is that some hard water crud will lodge in the valve. This isn't a problem with regular globe valves, since the twisting motion grinds away hard water deposits, but a spring valve like the TP valve is apt to have this problem.
If the valve does get crud in it, snapping it open and closed a few times may clear the crud (or it may simply draw more in).
Of course, once a valve has had seepage for any length of time the valve surfaces erode to the point where it never will close completely.
Clay...actually, they put up two houses down the street this past month...perhaps that did increase our water pressure?
So what's it take to get a pressure test? Is that a 'call someone in' type of thing?
As for not testing the valves...well...dang it. I did that too. Ugh! ;o)
The plumbing supply and HD sometimes has the pressure gauge that screws on to the hose bib (faucet). If the gauge reads over 90 lbs psi, you need a regulator. The pressure gets higher after midnight when no one else uses water. If there are houses up the hill from you, for sure your pressure is too high. If you have a pressure regulator, see ithe arrow on it is pointing in the direction of the water flow (backwards regulator sometimes causes problems)
You can put together a cheapo pressure tester, it needs to have a hose hook up to like 1/2"pipe thread to 1/4" for the gauge. some times sprinkler install area will have them in HD. An air gauge will work not the best but it will work. Keep it high so water doesn't get in it. I made up a test kit with all kinds of ends so I could check faucet aerator ends/ hose bibs/ iron pipe thread etc.. Its all in a paint can for when I need it. Plus if I look I Know that Johnstone Supply has testers but for this you can put one together.
Take and trip the relief valve a couple of times, open and snap let it close hard open snap back, if it's going to seat at all that will do it. House pressure should be around 55 lb. All new systems must have pressure regulating and check valves. So I think thats what way you are heading.
Yeah, open the relief valve and let it snap shut a few times to seat the gasket.
Ditto what Dan said. You most likely need an expansion tank.
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Put a piece of newspaper down to see if it's comming out of the relief valve. Easy to see where the wet comes from.
about 2 years ago I had a run of the HWHs from Hd with bad relief valves. after about 3 months they would let lose. Like the spring in the relief valve would lose it's temper or bad metal run or? so before reinventing the wheel the 10$ fix would be best.
Clay:
That might be it.
I got some time this evening to check it out a bit more. The 'leak' is just a slow, steady drip from the relief valve/pipe. The water coming out of it is barely room-temperature. Does that sound like a loose valve? How hard is it to change one of these things?
Also, the cold water inflow pipe is quite warm. Is that normal?
To replace the relief valve shut of the water feed to it, and open up a hot tap or trip the relief valve to release the pressure. Then dismantle the drain pipe from it ? copper/sweat you might have to cut the drop so you can unscrew the horizontal leg. Since it's new the old one should screw out fairly easy, use good size pipe wrench. Use good amount of pipe dope or teflon dope on new one.
Before I did any of that I would do a pressure check on you water system. If its running unusually high that could be the real problem.
I had a house that had no pressure regulator and the water was running 135lb and at night the local uphill tank would fill and they would get 155lb at the house. So if it's running high and then the heater boosts it up past the relief valve setting. Don't replace with higher pressure valve. You have to step down the pressure.
Clay
Also reguarding the water being hot at the infeed. Usually there is a internal check valve that prevents backflow. Minor heat transmited will warm it some what, especially if it hasn't been used for awhile.
Yeah, if it's a slow, steady drip from the relief valve it may be a bad valve. Shut off the heater, shut off the cold water to the heater, open a hot somewhere on the same floor. If there is a floor above, open a hot there to let the pipes drain.
If the pipe from the relief valve is copper, cut it a few inches from the valve on the horizontal leg, unscrew the pipe stub, then unscrew the valve. (It may help to have a helper hold the heater while you wrench the valve -- they can get stuck pretty bad.) Replace the valve, sweat a union on the cut ends of the pipe, and thread the stub into the valve (with teflon tape). Join the rest of the pipe at the union, turn on the water and check for leaks. Don't forget to turn the heater back on, or your SO will be PISSED.
It's normal for the cold water pipe to be warm (due to convection) if no hot water is being used. In newer installations there's supposed to be a check valve of sorts in the cold water inlet to prevent back flow, but that only sorta works.
From what I understand a little squirt once in a while is not uncommon. An expansion tank would prevent this I hear but most installations I have seen don't have one.
I was told, by a plumber, that the valves get weaker with time so replacing it might help. I have seen these valves, the few I have played with, leak because of hard water. The flakes can get lodged in the valve making it leak all the time. The one at my house sometimes gets a flake in the wrong spot while venting and I have to manually open the valve to clear it.
One or two good blasts and it seals for another six months. Used to do it more often but I cleaned the tank some time ago and it settled down to a steady once or twice a year. I need to clean the tank again but it is a low priority. Water heater is a full twelve years old so I wonder how much life it has left. hate to spend a couple of hours pampering it only to have it fail the same week.
I f you follow the thread he says its a pretty new HWH and it all had been working for some time and he replaced the RV. So something had changed to cause the problem?
Now if you want the HD cure just put a 175psi valve on it(Joke).
Yea...to clarify, it's a farily new heater (less that 2 years old). And that I've never had this problem up until maybe a month ago. Maybe coincidently, maybe not, they began construction on two homes up the street (literally 'up' the street as I am on a hill).
I put the new valve in yesterday, let it fill up, and it was fine. Came back a few hours later and noticed the bucket underneath the pipe had about an inch of water and it was dripping fairly constantly. I turned down the heat slightly and did the 'snap' thing with the valve. As of this morning, there's just a few drops in the bucket, so perhaps that was the culprit.
I'll watch it for a few days. If it still leaks, then I'll do the pressure test.