Basic Product Features

Water Heater Components

Water Heater Storage TanksStorage water heaters operate on the principle of heating water via either electric elements, or through combustion of natural or liquid propane (L.P.) gas, and the resulting transfer of generated heat into the water. The storage tank is designed with special features to ensure reliable, safe operation and long tank life, as well as to efficiently collect and retain the heat transferred to the water.

Primary features of the tank are the anode rod and the ceramic lining, designed to resist the corrosive effects of water (especially heated water) upon the steel tank. All tanks include safety measures to avoid pressure buildup beyond the tank limitations, in the form of a Temperature & Pressure Relief Valve, often referred to as the T&P Valve. The storage tank is well insulated to minimize heat loss while the water waits to be used by consumers. And finally, every water heater includes features for bringing cold water into the unit, sending hot water out of the unit, and draining the unit in case of service procedures. The features common to both electric and gas water heaters are explained in the following section.

Water Heater Outer JacketOuter Jacket - The outer jacket of a water heater consists of three pieces: jacket top, jacket skirt, and jacket bottom. The jacket provides a space for insulation around the tank, preventing the consumer from coming into contact with hot surfaces and to reduce energy loss. Connections extend from the tank through the outer jacket to provide plumbing connections for the cold-water inlet and the hot water outlet. The jacket base assembly is where combustion takes place in a gas water heater, and it is designed to shield the floor from excessive temperatures. 

Ceramic Lined Tank - A water heater tank is constructed of three pieces of steel: a top head, a bottom head, and a shell. These three pieces are welded together to form a tank that will withstand a working pressure of 150 pounds per square inch. The interior of the tank is coated with a ceramic material, baked on at about 1600°F, which will not break or crack, unless it receives a blow severe enough to dent the steel tank. This coating helps protect the tank from the corrosive effects of hot water. In addition to the top head, bottom head, and shell, the gas water heater also has a flue running through the center. As combustion occurs below the bottom head, heat rises into the flue. The flue contains a baffle, which is designed to increase the transfer of heat along the flue pipe and decrease the temperature of gasses as they exit. Both the tank and the flue are ceramic coated to prevent corrosion. On FLAME LOCK® water heaters the flue is ceramic coated on both the inside and outside. Water Heater Insulation 

Insulation - Water heaters have a layer of insulation between the tank and the outer jacket. Three materials are used as insulation in water heaters: non-CFC polyurethane foam, fiberglass, and polyester. Non-CFC polyurethane foam is the more efficient of these materials and is injected through a port in the outer jacket in liquid form. This liquid expands quickly, filling in the space between the tank and jacket, and then dries. Polyester or fiberglass is used around all openings and controls to ensure that the non-CFC polyurethane foam does not cover these devices. A fiberglass blanket is used around the combustion chamber of gas models due to the high temperatures radiated through the combustion chamber walls during burner operation. Water Heater Dip Tube 

Dip Tube - The dip tube moves incoming cold water to the bottom of the tank, preventing it from mixing with the stored hot water at the top of the tank. Dip tubes are designed to withstand high water temperatures and are made of materials such as polypropylene, polysulfone, and cross-linked polyethylene. Some dip tubes include integral heat traps that prevent heat from transferring back into the plumbing lines, while others are designed to reduce sediment buildup in the tank. In gas water heaters, incoming water sometimes causes condensation of flue gasses to occur, which can cause a sizzling sound when water droplets fall onto the burner below. This occurrence is not detrimental to the operation of the water heater.Water Heater Heat Traps

Heat Traps - In some models, heat traps are installed at the hot water outlet and cold-water inlet to reduce standby heat loss. The heat trap saves energy by preventing hot water in the tank from rising into the plumbing lines. Heat traps can be installed internally or externally. Water Heater Anode Rod 

Anode Rod - The anode rod is a sacrificial part, factory installed in the tank to reduce tank corrosion. A tank full of hot water acts very much like a battery, with small electrical currents flowing between the different types of metals. The anode rod is made of aluminum, magnesium or other alloys, which is more conductive than the steel of the tank. The electrical currents corrode the anode rod rather than the tank. Water Heater Temperature and Pressure Relief Valve 

T&P Valve - The T&P Valve, or Temperature and Pressure Relief Valve, is a safety device designed to relieve excessive pressure on the tank, preventing it from bursting. This valve activates by discharging water if the temperature inside the tank reaches 210°F. The T&P valve must never be altered, restricted, or blocked, as this creates a hazardous situation where the tank could build up pressure and possibly burst. Water Heater Drain Valve 

Drain Valve - A child-resistant drain valve is located near the bottom of the water heater. It provides a way to drain the water from the heater for maintenance purposes.