Among the a variety of security features built into a modern hot water heater, maybe the most crucial is the pressure and temperature relief valve. Also known as the T & P or TPR valve, this distinctive safety valve is mainly responsible for making sure a warm water heater stays within its intended temperature and pressure limits. If something goes wrong, the valve opens to release excess pressure by means of a discharge line. Replacing a relief valve isn’t a challenging procedure, but maintain your main pipe wrench handy if corrosion on the threads makes the old one difficult to eliminate.
Turn the hot water heater control valve to the off position and the temperature dial to its smallest setting. Turn off the water supply to the heater in the valve located on the cold water running into the tank. Instead, switch off the water in the home supply valve.
Open a hot water tap to release stress on the lines. Position a 5-gallon bucket under the tank drain valve. Drain enough water in the tank to deliver the level under the relief valve. Normally, draining 5 to 10 gallons is adequate if the relief valve can be found toward the surface of a 50-gallon tank. Exercise caution during the draining procedure; the water is still very hot.
Look carefully at the relief valve discharge line, which should operate in a downward direction from the valve toward the bottom of the tank. It is possible to remove a direct line in 1 piece, but a few discharge lines are plumbed so they operate to a location other than the base of the tank, like a remote drain. Get the essential clearance to eliminate this type of line by cutting it with a hack saw or close-quarters tubing cutter in a point a minimum of two inches below the valve.
Catch the nut-shaped connector threaded into the relief valve by means of a pipe wrench or a large pair of slip-joint pliers. Turn the port and attached part of discharge line counterclockwise to remove it in the valve. Set the discharge line aside for reuse.
Eliminate the relief valve in the hot water heater by turning it counterclockwise using a large pipe wrench. Based on the time of the valve, considerable force is often required. Clean the threads of the relief valve opening by means of a wire brush, then wipe off any debris using a rag. Discard the old flashlights or set it aside for recycling.
Apply sealant to the threads of the new relief valve. Insert the valve into the opening in the tank and thread it hand-tight. Tighten the valve three to four full turns using a pipe wrench. Expand the valve so the opening points downward toward the bottom of the tank.
Clean the threads of the discharge line adapter using a wire brush, then wipe off any debris using a rag. Apply sealant to the threads. Thread the connector into the relief valve discharge opening and tighten it with a wrench. The opening of a direct discharge line should terminate in a safe location within 6 inches of the ground, or as called for by the local plumbing code.
Repair the discharge line in the event that you cut it earlier. Clean the interior of a repair coupling and the exterior of both cut ends of the pipe with steel wool until they shine. Apply soldering flux into the interior of the coupling and the exterior of both pipe ends. Slip the repair coupling on the upper part of the discharge line. Position the lower part under the upper part, then slide the coupling down approximately 3/4 inch to join the upper and lower parts of pipe. Heating the connection using a propane torch and solder the joint.
Turn on the water supply to the hot water heater. Allow air to bleed out of the warm water lines through the tap you opened earlier, then close the tap. Flip open the lever to the relief valve for several seconds to check it for proper operation. Shut the valve and check for leaks.
Return the hot water heater into functioning mode after the manufacturer’s recommended procedure.