Water Heater Elements, Fittings and Add-Ons

Heating elements: voltage, wattage and thread have to agree

An electric element must match the voltage of the heater, such as 240 V or 208 V, and the wattage printed on the old element or the heater's data plate, such as 3000, 4000 or 4500 W. Putting a 240 V element on a 208 V supply gives much less heat, and the reverse can overheat. Titles also give length in inches and the mounting style, threaded or bolt-on flange; the new element has to fit the same opening.

Always cut the power at the breaker and drain the tank below the element before swapping it. An element run dry burns out in seconds, so refill the tank completely before switching the power back on. Some elements are low-density, which spreads the heat over a larger surface and lasts longer in hard water. Use a new gasket, tighten to the maker's spec, and keep the thermostat settings and wiring unchanged.

Pipe threads, temperature ranges and kit parts

Fittings and compact heaters list inlet and outlet connections in NPT pipe threads, 1/2 in or 3/4 in. NPT is a tapered thread, so it seals with thread tape or pipe compound, and connectors must match the size on both ends. Point-of-use heaters and mixing valves also list a temperature range, for example 95 to 140 degrees F, which is the output you can set. Flush kits are used to clear sediment and scale from a tank, and pilot assemblies are specific to the burner model.

Questions about Water Heater Elements, Fittings and Add-Ons

How do I know if my water heater element is bad?

Typical signs are lukewarm water, hot water that runs out quickly, or a tripped breaker. With the power off, a multimeter can test the element for continuity and for a short to the metal housing. Replace both elements in a two-element tank if one has failed.

Can I fit a higher-wattage element to get more hot water?

Only if the heater's data plate and wiring allow it. A higher wattage can overload the thermostat, wiring and breaker, and it exceeds the heater's rating. Match the original wattage, or a size the heater maker approves.

What is a flush kit for?

It connects a hose and valve to the drain so you can flush the tank and wash out sediment and scale that lower efficiency and shorten element life. Flush yearly, especially in hard water areas, and turn off power or gas before starting.