the water heater to be the most dangerous device in your house.
Water heaters are equipped with a temperature pressure-relief valve
(usually abbreviated TPV or TPR) that releases both hot water and
built-up pressure if either gets too high (usually 150 degrees or 300
pounds per square inch).
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
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.