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Know the Parts of Your Storage Water Heater and How They Work

Know the Parts of Your Storage Water Heater and How They Work

The storage water heater is still standard equipment in most residences. Over 90 percent of homes in the U.S. use either gas-fired or electric storage tank models and 90 percent of those are less than 55-gallon capacity. This is tried and true technology and—with new water heater sales averaging over 9 million units per year over the past decade—mass production to meet the universal demand continues to keep the cost of a new storage water heater competitively low.

Fuel Supply

About 53 percent of homes utilize gas-fired water heaters that burn standard natural gas supplied to the home. The remainder of storage tank models feature electric heating from a 220/240-volt connection.


Most water heaters utilize a conventional steel tank coated internally with vitreous glass to prevent corrosion. High-end heaters offer stainless steel tanks that offer longer expected service life than glass-coated conventional steel. Both types feature a cold water inlet and hot water outlet plumbing connection on the top of the tank. A replaceable sacrificial anode inside the tank attracts corrosives in the water to inhibit tank corrosion and prevent leakage.

Heat Source

A gas burner located beneath the tank heats water inside the tank. In an electric heater, two heating elements inside the tank—one near the bottom and another midway—convert electric current to resistance heat. Both gas and electric models feature thermostats that sense water temperature and automatically cycle the unit on and off to maintain the selected thermostat setting. For safety reasons, water temperature is usually set to 120 degrees or less.

Temperature And Pressure Relief Valve (TPR)

Screwed into a threaded outlet on the side or top of the tank, this spring-loaded valve automatically opens if water temperatures reach 210 degrees Fahrenheit and/or internal tank pressure reach 150 p.s.i. This safety device prevents dangerous rupture or explosion of the tank should the burner or electrode fail to shut off. TPR valves should be tested annually to ensure proper operation.

For professional storage water heater sales and service, in Broken Arrow contact Air Assurance.

Our goal is to help educate our customers in the Tulsa and Broken Arrow, Oklahoma area about energy and home comfort issues (specific to HVAC systems).  Credit/Copyright Attribution: “Clipart deSIGN/Shutterstock”