Repairing a hot water heater pressure relief valve is not that difficult. Usually 'repair' means 'replacement'. The parts are inexpensive and it takes less than an hour. See 'Troubleshooting Hot Water Heaters', if this is not your problem.
There are (2) options with the valve. 'Flushing Out a Pressure Relief Valve' will help you check to make sure it is seating correctly. 'Replacing a Pressure Relief Valve', is the more common scenario.
A pressure relief valve, well, as the name implies relieves the pressure in your tank. Heated water generates pressure. Should that pressure go beyond what it considered safe or into the danger zone. The lowly valve acts as a safety feature. It relieves the pressure before your hot water tank blows up.
So what happens when the valve fails. Does the tank blow up? You would see a lot of 'film at eleven' spots if it did. Instead, when it fails it goes the other way. It starts releasing pressure before the danger level. What does that mean exactly? It means hot water spraying all over the place around your hot water tank. Basically a mess.
Not a lot of options when this happens. Installing a new valve is usually the fix. Read on and see if you are up for the challenge.
A new valve is less than $20. I don't want to upset you, but, when they start acting up they are usually terminal. Call in the family and get the arrangements worked out. $100 to $150 to have someone come out and change it. It takes a half an hour, you be the judge.
Replacing a hot water heater pressure relief valve is not that hard, it will take less than an hour, including the trip to the supply store. Do you live in Montana? Maybe a little longer.
There is a chance that something got caught in it. How did that happen? It hasn't moved in years. I said a chance, take a look at Step One.
You don't have a lot of choices here. You cannot use the hot water tank without the hot water heater pressure relief valve installed. No hot water is no fun, no other way to put it.
The 'Next' section discusses 'Checking a Pressure Relief Valve'. Check the 'Home Repair Topics Menu' at the top of the page, if this is not your problem.
Checking a pressure relief valve can tell you if it needs to be replaced. Since it is some work and cost to replace it, you want to check first.
It is possible the water heater pressure relief valve is not seating correctly. The find out you will need to open it up a few times to blow off some of the water. The water will wash out any sediment or obstructions.
Before you do this you are going to want to cool the water down. Shut off the power to the hot water tank. For and electric hot water tank you can shut of the breaker. On a gas hot water tank, you will want to turn the gas valve to 'Pilot' or 'Off'. Run hot water into a sink or tub. When the water is lukewarm and not dangerous you can stop.
Get a pail to catch the water from the valve. You want to hold the pail under the outlet when you release the pressure. The valve does not turn, instead you lift it up to open it. Open the valve or a few seconds and then close it. Do it a few times.
Turn the power or gas back on and let the water heat back up. See if the hot water heater pressure relief valve holds. Is it holding? Yes, well that is good news. NO? Then you will need to replace the valve. Go to Step Two
WARNING!! The Water In Your Hot Water Tank Is EXTREMELY HOT!!! WARNING!!!
The 'Next' page covers 'Replacing a Pressure Relief Valve'. The 'Previous' page is the 'Introduction' to this series of articles on 'Water Heater Pressure Relief Valves'.
At this point you can unhook the hose at the drain valve. You may have a little clean up to do. Turn the water back on and let the tank fill back up. When the tank is full, check for leaks around the new hot water heater pressure relief valve. Not leaking? Good Job!
For an electric heater you want to turn the breaker back on. Gas hot water heaters need to have the gas valve turned to on. Make sure the pilot is still lit and it fires up when you turn it on. After the water heats up you can double check the valve for leaks. That's it, you're done.
Before replacing a water heater pressure relief valve, you need to get a new one. They are less than $20 at a home or plumbing supply. There are different pressure and temperature ratings. A standard one would be 150 psi and 210 degrees for temperature. There should be a little plate on the valve that gives you these figures. Take the old one with you and get one that matches.
To change you water heater pressure relief valve you are going to need to drain the tank down part way. Turn the breaker off or turn the gas valve to pilot. Run some hot water in one of the faucets until the water is lukewarm.The water coming out of the tank will be pretty hot if you don't cool it off. Shut off the cold water inlet valve. Hook up a garden hose to the drain valve at the bottom of the tank. Run the hose to a floor drain or bathtub nearby. You need to drain the water down below the water heater pressure relief valve.
There is no good way to tell what the water level is in the tank. Go with how long it takes to fill a bathtub. That will be plenty. If water starts gushing out when you loosen the valve, you need to drain some more water.
You will need a pipe wrench to remove the old water heater pressure relief valve. You may or may not have a outlet tube attached to it. Remove it first. Save the tube you can re-use it with the new valve. Clean it up, as required.
With the outlet tube removed you can take out the old pressure relief valve. It will take a bit of effort to get it loosened. Remove the old valve and clean up any residue around the opening. I am not aware of any arts or crafts that use old pressure relief valves, so you will probably just want to throw it away.
Put some pipe dope or Teflon tape on the threads for the new water heater pressure relief valve. Thread the new valve into the opening and tighten it down. The outlet should be turned down. Put a little pipe dope or Teflon tape on the nipple for the outlet tube and then install it.
The 'Next' section is a 'Summary' for this series on 'Water Heater Pressure Relief Valves'. The 'Previous' section covers 'Checking a Pressure Relief Valve'.
The 'Introduction' to this series on 'Water Heater Pressure Relief Valves' gave you some information on the possible costs if you have to call a plumber to fix this for you. In addition, some easy fixes and potential problems were discussed.
It is possible that the valve was not seated properly. So the article 'Checking a Water Heater Pressure Relief Valve', covered ways to check and make sure it is seated correctly.
Changing the pressure relief valve is not a big job and they are fairly inexpensive. The article 'Replacing a Water Heater Pressure Relief Valve' covered the steps involved.
There are not many options for a troublesome water heater pressure relief valve. Once in awhile the valve gets something it and it won't seat properly. As a rule the valve works without complaint for years and then one day it starts venting. All of us do that from time to time, can we blame the valve?
The usual solution is to replace the valve. It is not that big of a job and the part is not that expensive. You should have paid about $15 dollars for a new valve. Hopefully you were able to deal with your valve.
The 'Previous' page discusses 'Replacing a Water Heater Pressure Relief Valve'.