How to Repair an Electric Wall Heater

How to Clean a Wall-Mounted Electric Heater

1. Turn Off the Power

   At your home's electrical service panel, turn off the circuit breaker that controls your wall-mounted heater. With 120-volt heaters, this will be a single-pole circuit breaker. A 240-volt heater will be controlled by a double-pole breaker, which usually consists of two circuit breakers tied together with a wide toggle switch. Occasionally, you will find that the 240-volt breaker is a slim-line, narrow-body breaker.

   Flip the breaker lever to the OFF position. However, never assume you have turned off the correct breaker until you have tested the wires inside the heater. It is very common for circuit breakers to be mislabeled in the panel.

2. Clean and Remove the Grille

   While the grille is in place on the heater, clean out the slots with the shop vacuum. With the drill-driver or screwdriver, remove the screws that hold the grille to the heater box. Set the grille and screws aside.

3. Check for Power Inside the Heater

   After first testing the voltage detector on a known live wire, test the inside of the wall heater to make sure that no power is present. Test at various points throughout the heater, focusing on the connections where the circuit wires and wire leads are joined. If the tester does not light up, then the circuit is off and it is safe to touch the wires.

4. Check the Wire Connections

   The electrical circuit cable that enters the heater box (usually an NM or plastic-sheathed cable) attaches to a set of wire leads that are soldered onto the heater. The two sets of wires are usually joined together with wire connectors (wire nuts).

   Check the condition of these connections. If they are loose, re-attach them. If necessary, you may need to strip away some additional insulation from the circuit wires or wire leads in order to join them securely. Make sure there is no exposed wire visible beneath the wire connector. Some electricians like to wrap the base of the wire connector with electrical tape for a secure hold.

5. Examine the Wire Insulation

   The outer insulation of all wires should be solid and free of nicks or cracks that might cause a short circuit. For minor nicks, wrap the wires with electrical tape. Badly degraded wires indicate a heater that has outlived its lifespan and needs to be replaced.

6. Clean the Heater's Electric Coils

   With a thin nozzle attached to the shop vacuum, clean out the heater's electrical coils to remove all dust. Dusty heating coils can cause overheating and premature failure of the heater.

7. Inspect the Cleaned Coils

   Check inside of the heater to confirm that all debris has been removed from the coils. The coils must be spotless. Any debris left on the coils will smoke and possibly even catch fire.

8. Inspect and Clean the Fan

   Carefully vacuum out the heater's fan with the shop vacuum. Be careful not to dislodge or damage the delicate vanes of the blower fan. Spin the fan by hand; it should spin freely.

Troubleshooting Electric Wall Heaters

The Wall-Mounted Heater Has No Power

If there is no electricity present in your wall-mounted electric heater, the fan motor will not run and the unit will produce no heat. There are several common causes for this problem:

The circuit breaker is off: If the circuit breaker has tripped or been turned off for some other reason, the heater will not function. Check the circuit breaker and reset it to the ON position, then check the heater for operation.

The circuit is overloaded: If the circuit breaker trips at irregular intervals, it is possible that the heater is drawing more current than the circuit is intended to handle. This sometimes occurs if the heater circuit is also supplying power to additional outlets or fixtures. A wall heater generally should be powered by a dedicated circuit that powers no other devices in the house, but even here, a large heater powered by a circuit with insufficient amperage sometimes can cause an overload. If the heater circuit trips regularly, it's probably time to have an electrician look at the situation and make whatever circuit corrections are necessary. Or, the heater can be replaced by one with a lower power demand.

The circuit breaker is defective: Although it is not common, circuit breakers sometimes do fail. AFCI and GFCI breakers, in particular, can be so sensitive that they frequently cause nuisance-tripping. A faulty circuit breaker should be replaced by an electrician.

The wires are short-circuiting: Short circuits are caused when electrical current flows outside the established wire connections and finds a "short circuit" back to the ground. This is potentially quite a dangerous situation that can lead to shock or fire, so it should be addressed immediately. Short circuits are sometimes accompanied by sparking or the smell of burning plastic. And if a circuit breaker trips again immediately each time it is reset, it's likely you are dealing with a short circuit. Some short circuits are easy to spot and fix if they are caused by simple loose wire connections. But problems with the internal wiring of the heater or circuit wiring problems call for an electrician's expertise.

The Fan Is Slow or the Heat Is Weak

When your wall-mounted electric heater's blower fan runs slowly or the amount of heat is inadequate—and you have already cleaned the unit and checked for physical blockage—the circuit voltage and the heater power requirements may be mismatched. This usually occurs if a 240-volt heater has been incorrectly wired to a 120-volt circuit, and it's almost always a sign that the work was done by an amateur with a lack of understanding. In this instance, you should have the heater replaced with a proper 120-volt model.

However, there are also convertible wall heaters that can be properly wired for either 120-volt or 240-volt circuits. There is nothing wrong with wiring such heaters either way, provided the connections are made according to instructions. Properly wired, these heaters will run adequately in either configuration.

The Heater Keeps Turning On and Off

A heater switching on and off repeatedly could be caused by an item blocking the unit's airflow, like a curtain, paper, or plant. Check to see if anything is blocking the air intake. Also, clean the vent cover or replace a dirty air filter (if your unit has one). And check that the blower wheel isn't covered in dust, dirt, or gunk.

Another culprit could be that your thermostat is on the fritz. The control switch could be malfunctioning, it may need new batteries, or the wiring could be old or faulty. Sometimes the thermostat's location, such as the sun hitting it at certain times of the day, can also cause the thermostat sensors to skew the temperature readings, making it act wildly.

The Heater Turns On but Doesn't Heat

If the heater turns on, but no heat comes out, it could be the heating element. The heating element is the part of the heater that gets hot and converts the electrical energy passing through it into heat, radiating out from it and making the area hot.

To check the thermostat heating element and its wiring, remove the thermostat knob, control knob, and faceplate. Then remove it from the wall (once all power is cut to the unit) and check all the wiring. Tighten any loose connections. Similarly, check that no obstructions are affecting the airflow. If this does not fix the problem, the electric wall heater may need a new heating element.

The Heater Smells Like It's Burning

When dust, hair, or other debris comes in contact with the heating element while it's on, the high heat from the heating element can singe and burn those items, giving the room a burning smell. This dirt can pose a fire hazard or destroy the heating element. To clean the heating element, open the housing and vacuum to remove the dust and debris.

If it smells like an electrical fire—a distinctive coppery or metal smell—it can be faulty wiring catching fire. Turn off the system immediately and call a heating, ventilation, and air conditioning (HVAC) technician to evaluate the problem.

When to Call a Professional

Because repairing a wall-mounted electric heater involves your home's electrical system, call a licensed electrician or HVAC technician if you feel uncomfortable with any aspect of electrical work, especially with changing circuit breakers or wiring work.