Many consider the water heater to be the most dangerous device in your house. Water heaters are equipped with a temperature- and pressure-relief valve (usually abbreviated TPV or TPR) that releases both hot water and built-up pressure if either gets too high (usually 150° F, or 300 pounds per square inch/psi). If the valve malfunctions, the heater can explode. Carefully test your valve periodically by quickly tripping its test lever. If water pours out of the discharge tube, the valve is clear of deposits and capable of performing its job. If it has been a while since you've performed this test, or if the valve is old, be aware that it might become stuck in the open position during testing. Before you begin, know the location of your main water shutoff, in case this happens.
