Things You'll Need
Pipe Thread compound
A heat trap nipple reduces a water heater's energy consumption. Heat trap nipples prevent heat loss through the water pipes connected to a water heater's inlet and output ports. A heat trap nipple uses a flapper- or ball-style check valve to hold the water heater's heated water in the tank until one of the building's hot-water faucet valves turn on. When the faucet valve turns on, the check valve opens and allows unrestricted water flow into and out of the water heater.
Coat the ends of each heat trap nipples' threads with a pipe thread compound. A water heater uses two heat trap nipples. Each heat trap nipple contains a color-coded check valve and has two sets of threads.
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Spin the threads on the heat trap nipple with the blue-colored check valve into the water heater's inlet port, usually labeled "Cold." If the heat trap nipple has an arrow on its side, face the arrow toward the water heater. Hand tighten the heat trap nipple.
Twist the threads on the heat trap nipple with the white- or red-colored check valve into the water heater's outlet port, usually labeled "Hot." If the heat trap nipple has an arrow on its side, face the arrow away from the water heater. Hand tighten the heat trap nipple.
Tighten each heat trap nipple with a pipe wrench.
Connect the building's cold-water supply pipe's fitting to the heat trap nipple with the blue check valve. Tighten the water pipe fitting with an adjustable wrench.
Attach the building's hot-water supply pipe's fitting to the heat trap nipple screwed into the water heater's hot-water port. Tighten the water pipe fitting with the adjustable wrench.
Never apply heat with a torch to a heat trap nipple. The check valve will melt or deform.