A 30-gallon water heater can explode with the same force as one pound of dynamite, causing significant damage and destroying your home, according to Watts Water Technologies. Having a temperature and pressure relief valve installed in a water heater reduces that risk, if it works properly. T&P valves are designed to open and relieve pressure buildup inside the tank, regulating the tank pressure at 150 pounds per square inch. They also act as a temperature regulator. If the water rises above 210-degrees Fahrenheit, the valve will discharge overheated water to reduce the temperature. Check your T&P valve regularly to avoid damages.
Find the temperature and pressure relief valve on your water heater. It could be on the side of the tank, on the top of the tank or attached to the line delivering hot water to your home. It is made of brass or bronze and has a small test lever attached to the top. A CPVC drain line attaches to the valve, and usually terminates at the bottom of the water heater into a floor drain or pan.
Feel along the relief valve drain line with your hands. The drain line should feel cool to the touch, except where it connects to the valve. If your drain line feels hot, the relief valve is open and needs replacing.
Lift the test lever on top of the temperature and pressure relief valve. This should release a small amount of steam and hot water from the tank. If you can't lift the lever or the valve does not release water or steam when you do lift it, the valve needs replacing.
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