Electric Wall Heater Not Working? Reset, Clean or Replace

Check the thermostat and the breaker first

The thermostat. Cadet’s Com-Pak instructions are to turn the knob fully clockwise, then back counterclockwise once the room is warm. Its list for a heater that does not run starts with a thermostat set too low.

A digital Cadet Energy Plus. Cadet lists the heater sitting in FAN mode at 0 as a reason it does not heat or blows cold air: press the mode button to switch back to HEAT. A temperature lock can also keep it low.

The breaker. Cadet says electric heaters must be on a circuit used only for heaters. If its breaker is off, turn it back on. If it trips again straight away, Cadet’s causes are the wrong supply voltage, an overloaded circuit, a short circuit or a faulty breaker, and it says not to reset the breaker until any short is repaired: a breaker that keeps tripping.

Reset the overheat safety the maker's way

Cadet Com-Pak and Com-Pak Twin. Cadet says the manual power reset limit opens when the heater gets too hot, and it can be reset at the thermostat or the breaker. Turn the thermostat below room temperature, wait at least 20 minutes, fix whatever caused it, then turn the thermostat back up. Cadet says the standard built-in thermostat has no off position, so if the fix means taking the grill off, use the breaker way instead. If it does not come back on, turn its breaker off, wait at least 20 minutes, fix the cause, then turn the breaker and the thermostat back on. Cadet recommends the breaker method if the room is below 45°F.

Why the wait matters on a Com-Pak. Cadet says restoring power, even briefly, heats the limit again even if the heater does not come on, so the 20 minutes starts over every time the power goes off and on.

Cadet Energy Plus. Turn the power off at the main panel, allow 10 minutes to cool, make sure the heater is not blocked and is clean, push the reset button, and restore the power.

King WHF. King says its Smart Limit Protection stays off until the heater is turned off for fifteen minutes. Check for anything on or near the heater, and if it shuts off again, turn it off at the breaker and check for a failed fan motor or dirt and lint on the element.

Marley Smart Series. A red light, a beep and ES flashing in turn with the temperature mean the thermal limit has tripped and the buttons are locked. Marley says that once it cools, the red light flashes, and holding the POWER and UP buttons for 1.5 seconds resets it. If it shows E1, E2, ES on its own, or ES with E1 or E2, Marley says that is a fault: turn the power off at the main panel and call its technical support.

If it will not reset at all. Cadet says the Com-Pak also has a backup over-temperature fuse that opens in a severe overheat, and then the heater must be repaired or replaced. Marley says of its one-shot backup protector: if it opens, the heater has to be replaced. Cadet, King and Marley all say never to tamper with the overheat limit, and King and Marley say never to bypass it.

Clean it, with the power off

Why. Cadet says the limit typically trips because the heater is blocked or needs cleaning, and lists dust and lint inside as one cause of smoke or a burnt smell. Cadet says to clean its heaters at least every six months; King says once a year.

Cadet’s steps. Let the heater cool, then turn the power off at the breaker before removing the grill. Cadet warns this is to prevent serious shock, burns or death, and says to lock or tag the panel door so nobody turns it back on. Cadet also warns breakers are often not marked correctly, so make sure the power is really off before you reach in, and to call a qualified electrician if you are not comfortable doing this. Holding the fan so it does not bend, blow the debris out through the element with a hair dryer or a vacuum on its blow setting without touching the element, and put the grill back before turning the power on.

Both Cadet guides. Cadet adds washing the grill in hot soapy water and drying it, and vacuuming the fan without touching the element. Cadet says never to oil the motor.

On a Marley Smart Series. Marley’s owner cleaning is the outside only. Turn the power off at the main panel first, because Marley notes power is still live to the heater when its POWER button has turned it off. Once it is cool, vacuum the grill openings with a brush attachment and wipe the grill with a damp cloth. It says a qualified service person should clean inside it at least once a year.

Painting the wall. Cadet’s Com-Pak guide says the warranty is void if anything is sprayed on the element or blower, and to mask the heater when walls are painted or textured. Cadet also says not to use the heater where paint or other flammable vapors or liquids are used, because it has hot and sparking parts inside.

Keep the front clear

The makers’ numbers. Cadet says to keep cords, curtains, furniture and other things that can burn at least 3 feet from the front of a Com-Pak and 6 inches from its sides, and Marley gives the same 3 feet for the front. King says its heater must not be installed less than 6 inches from a side wall or the edge of a door. The makers all say extreme caution is needed when a heater is used by or near children, and Cadet says to keep all foreign objects out of it.

Where it must not be. Cadet says never in a floor, below a towel bar, behind a door, or anywhere its air can be blocked, and never directly above a bathtub or sink or in a shower area. It recommends at least 2 feet from them, and says the Energy Plus must be on a GFCI protected circuit in a bathroom.

If it keeps tripping. Cadet’s Energy Plus chart gives blocked airflow as the reason: remove the obstruction and keep the clearances. Cadet says a heater whose safety trips more than once a day must be replaced, and Marley says not to keep using a heater that keeps tripping after being reset. King says to turn the power off and have a heater whose limit keeps shutting it off checked by a qualified electrician, and Marley recommends an electrician’s check if it tripped with nothing blocking it.