Basic Components
Cold Water Inlet Pipe
The inlet pipe (usually copper) is connected to the main cold water supply pipe and provides water to the tank. The average temperature of the incoming cold water is 50° F.
Cold Water Control Valve
The cold water control valve allows the incoming cold water to be turned on and off. The valve may be turned off when the water heater is not in use, in an emergency when the water heater leaks, or when the water heater is being replaced or breaks down .
Cold Water Dip Tube
To prevent the incoming cold water from cooling the hot water leaving the tank (at the top), the cold water is introduced at the bottom of the tank (which is also closer to the heat source). When the cold water inlet pipe is located at the top of the tank instead of at the bottom of the tank on the sidewall, a dip tube is used to direct the cold water to the bottom of the tank.
Hot Water Outlet Pipe
The outlet pipe is a short pipe that extends into the top of the tank. Since the water at the top of the tank is generally hotter than the bottom (heat rises), the hot water is always taken from the top. The average temperature of the hot water is 140° F, however, for safety and energy conservation reasons, water heaters are often set to 120° F.
Anti-Corrosions or Sacrificial Anode
A rod placed in glass-lined metal water heater tanks to help prevent the tank from rusting (oxidizing). The anode rod, usually made of magnesium, attracts the corrosion-causing oxygen in the water. The rod protects the tank from eroding, and eventually wears away. The rod must be replaced to prevent the metal tank corrosion from accelerating. Replace the anode every year or as necessary.
Drain Valve
The drain valve at the bottom of the water heater allows the tank to be drained. Sludge or sediment from the water or the sacrificial anode will collect at the bottom of the tank over time. Excessive sludge/sediment may lower the water pressure or reduce the water heating efficiency. Recommended maintenance includes draining the sludge once a year.
Temperature Pressure Relief Valve (TPRV)
The temperature pressure relief (TPR) valve is a safety device that is designed to:
- prevent the water in the tank from exceeding 212° F, and
- prevent the water pressure in the tank from exceeding 150 pounds/square inch (psi).
A tube or pipe that is attached to the TPR valve to direct the superheated water down to the floor and away from anyone in the discharge area in order to prevent scalding or burning.