Relief Valve Problems on a Hot Water Heater

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A few different problems could potentially crop up with the relief valve on your hot water heater. Find out about relief valve problems on a hot water heater with help from an area manager for Roto-Rooter Plumbing & Drain Service's Independent Contractors Division in this free video clip.

Part of the Video Series: Hot Water Heaters
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Video Transcript

Every water heater should be equipped with a temperature and pressure relief valve. This is a crucial safety device that is mandated by all plumbing codes and it should never be removed or disabled. I'm Dave Jones, master plumber for Roto-Rooter Plumbing and Drain Service and I'm going to discuss problems that sometimes occur with the temperature and pressure relief valves on the water heaters. Relief valves discharge for usually two reasons. One, there is excessive pressure building up inside the system that has exceeded 150 pounds of pressure or two, the temperature inside the tank has exceeded 210 degrees Fahrenheit. Both these situations can be very dangerous and the temperature pressure relief valve will open to prevent an explosion. If you notice water on the floor around the water heater and there's no evidence of a tank or plumbing leak, it is probably a sign that the water heater's temperature and pressure relief valve has recently opened and relieved itself. First you should test the water pressure in the house by using a pressure gauge that will screw right onto a hose bib or a faucet. You can pick up one of these gauges at any home center. Most plumbing codes state that the maximum water pressure coming in that house should be 80 PSI or less. If the water pressure exceeds this amount, a pressure reducing valve will need to be installed on the water main. Note that the ideal water pressure is between 50 and 60 PSI. You want to make sure that the thermostat is not set too high. If the thermostat is set too high or it's faulty, the T and P valve will discharge to relieve the pressure inside the tank. Remember, for a standard water heater, the temperature should be set at 120 degrees Fahrenheit. You could try flushing the T and P valve to make sure it didn't become fouled by sediment and it's a good idea to test the T and P valve at least once a year to make sure it's operating properly. Simply place a bucket beneath the discharge tube. You just want to flip open the relief valve and let it run for about five seconds to make sure it opens fully. Stand back and don't do this if you are barefoot or wearing open toed shoes or sandals. If that hot water splashes out you could be burned. Remember, the T and P valve is the only thing that prevents your water heater from becoming a bomb. Once the valve snaps back, make sure it doesn't leak. If it does, you'll need to replace the valve. Next, check to make sure the expansion tank above the water heater hasn't failed. You can do this by removing the cap that's located on top of the tank and press in the Schrader valve. This is the same type of air valve that you'll find on tires to see if air or water comes out of it. If water is expelled from the valve, then the tank needs to be replaced. I hope this has helped and you have a better understanding of the temperature and pressure relief valve on your water heater. I'm Dave Jones, master plumber with Roto-Rooter. Thanks for watching.


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