40 gallon tank electric leaky PRV...

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wilshire

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Have an interesting one going on. house is vacant for time being so water heater has been off. Each time we fire it up, initially the prv leaks roughly half a cup of water. After this initial burst right when it heats up, no more leaks from popoff. Is this normal? Heater is <2 years old and has a thermal expansion tank on it.

Have bled a gallon or so out of prv and it doesn't leak after I closed it so don't think its faulty. Not sure if expansion tank is compromised as it's bolted to wall and hard to tell....any ideas? We are selling the house and hate to sell it with a leaky tank
 

Reach4

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Turn off the water and release the water pressure by opening a faucet. Check the air pressure on the thermal expansion tank. It should be at or a little above the setting for the pressure reducing valve or the maximum pressure that the city supplies if there is no pressure reducing valve. If the tank does not sound empty when you rap on it after the water pressure is down to zero, it is bad. If water comes out of the Schrader valve, it is bad. If the air pressure is low, try pumping it up and see if the symptom disappears.

Note that the thing on the side of the water heater is a usually called a T&P (temperature and pressure) relief valve. The term PRV is usually used to refer to a pressure reducing valve. Those are usually right after the cutoff valve where the water comes into the house.
 

wilshire

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alright so after depressing stem within Schrader valve, water came out so I think the tank is compromised. I have bought a new tank and have installed one of these years ago...basically just:

Turn off water
drain some water out of tank
unscrew old TE tank and screw new one in?
I will also check the PSI of the tank and make sure between 30-60psi

any other tricks to be aware of? Thanks for advice to check that may very well have saved me a service call
 
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Reach4

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If you have a water pressure gauge, measure the water pressure on your water while some faucet is on very low. Add about 5 PSI to that number to allow for the water pressure often being higher in the wee hours of the morning as the city tops up its water tank. Put that much air pressure into the empty tank. The tank does not need to be screwed into place at that point.

If you don't have, and don't care to get a water pressure gauge, here is a way to measure water pressure: connect the expansion tank, and turn on the water. Measure the air pressure in the pressure tank. Assuming the pressure is higher than it was before, that is your water pressure. Now turn off the water and reduce the water pressure to zero again. Add air to 5 PSI more than the inferred water pressure as measured by your air pressure gauge.

I am not a pro. Not everybody likes the same procedure. Some just use the air that came from the store. Some set the pressure to match the measured pressure. Some will set the air pressure to 70 or 80 PSI without measuring the water pressure. Except for the first method, it will probably work fine, and even that often works too. Naturally I think my method is better.
 

Jadnashua

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If you're thinking about draining the water, and it might drain the WH some, especially on an electric tank, shut the power off until it is refilled and you turn a faucet on to flush any air out. If the heating element is ever exposed, it will burn out almost instantly.
 

Jadnashua

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If you're thinking about draining the water, and it might drain the WH some, especially on an electric tank, shut the power off until it is refilled and you turn a faucet on to flush any air out. If the heating element is ever exposed, it will burn out almost instantly.

Make sure to use some tape and/or pipe dope on the threads of the fitting when installing the new ET.
 

wilshire

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Thanks ya'll....swapped it out and it was indeed waterlogged and not functioning. Put new one on and it filled up partially with water and no more spitting from T&P valve....Great success! Cheers.
 
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