How to Repair a Wall-Mounted Electric Heater

Fix Wall-Mounted Electric Heater
Lee Wallender
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    Wall-mounted electric heaters are a popular primary heat source for small rooms such as bathrooms and a supplementary heat source for large rooms that need extra warmth. Electric heaters help conserve energy by spot-heating particular areas, rather than heating the entire structure. Solid, dependable, and safe, wall-mounted electric heaters can be expected to provide reliable heat for many years.

    Yet over time, wall-mounted heaters may degrade in performance or stop working altogether. You may find that the blower is pushing out air, yet the air is not hot. Or the reverse: the heating element is hot, yet the blower has stopped working. Sometimes neither the blower nor the heating element will work. 

    For minor problems, you can easily fix your wall-mounted electric heater with a combination of cleaning, inspection, and tightening loose connections. In some cases, you may need to replace a faulty circuit breaker.

    Safety Considerations

    Wall-mounted electric heaters are hardwired into your home's electrical system and can draw as much as 240 volts. Always make sure that the circuit breaker controlling the heater has been turned off. Also, with a voltage tester, double-check that no current is flowing to the heater.

    Project Metrics

    • Working Time: 30 minutes
    • Total Time: 45 minutes
    • Skill Level: Beginner
    • Material Cost: $10 to $20

    What You Will Need



    • Wire nuts
    • Electrical tape

    When to Call a Professional

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

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    Turn Off the Power

    Shut Off Circuit Breaker to Heater
    Lee Wallender

    At your home's electrical service panel, turn off the circuit breaker that controls your wall-mounted heater.

    120V Heaters

    If this is a 120V heater, you will turn off a single-pole circuit breaker.

    240V Heaters

    If this is a 240V heater, you will turn off a double-pole circuit breaker. Usually, these are identified by the broad toggle switches that simultaneously control two single-pole breakers. However, sometimes 240V breakers are a slimmer, narrow-body breaker often called a tandem breaker.

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    Clean and Remove the Grille

    Clean and Remove the Grille
    Lee Wallender

    While the grille is in place on the heater, clean out the slots with the shop vacuum.

    With the cordless drill and a driver bit, turn out the screws that hold the grille to the heater box. Set the grille and screws aside.

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    Check Power Inside Wall Heater

    Check Heater Current With Voltage Tester
    Lee Wallender

    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.

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    Check the Condition of Pigtail Connections

    Check Condition of Pigtail Connections
    Lee Wallender

    The electrical cable that enters the heater box (usually an NM or plastic-sheathed cable) attaches to a second set of wires that are soldered onto the heater. The two sets of wires are pig-tailed (twisted) and covered with plastic wire nuts.

    Check the condition of these connections. If loose, re-attach. It may be necessary to rip back the sheathing to expose more of the wire, then strip back the wire casing.

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    Examine Wire Casing for Nicks

    Examine Wire Sheathing for Nicks
    Lee Wallender

    The casing of all wires should be solid and free of nicks or cracks that might cause a short circuit. For minor nicks, wrap with electrical tape.

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    Clean Heater's Electric Coils

    Clean Heater's Electric Coils
    Lee Wallender

    With a thin nozzle attached to the shop vacuum, clean out the heater's electrical coils.

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    Double-Check Condition of Cleaned Coils

    Double-Check Condition of Cleaned Coils
    Lee Wallender

    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.

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    Test Blower for Free Rotation

    Test Blower for Free Rotation
    Lee Wallender

    Vacuum out the blower (fan) carefully with the shop vacuum. Be careful not to dislodge or damage the delicate vanes of the blower. The blower should spin freely.

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  • 10 of 11

    When the Wall-Mounted Heater Has No Power

    If there is no electricity present in your wall-mounted electric heater, the cause might be:

    Circuit Breaker Is Off

    The circuit breaker has tripped off. In this case, turn off the heater and flip the circuit breaker back on. At the heater, turn the heater on.

    Circuit Breaker Is Defective

    While circuit breakers can last for years and even decades, sometimes they do fail. AFCI breakers, in particular, can be so sensitive that they frequently cause nuisance-tripping. 

    The solution is to install a new circuit breaker.

    Circuit Is Overloaded

    The total amperage draw for an electric wall heater is often limited to 80-percent of the total amperage rating for that circuit breaker and all supply wires.

    The immediate solution is to reduce the draw on the circuit from other devices. Alternatively, you can remove the existing heater and install another heater that draws fewer watts.

    Wires Are Short-Circuiting

    Short circuits are sometimes accompanied by sparking or the smell of burning plastic.

    Inspect the electrical supply wires for damage to the sheathing. Inspect the points where the wires connect to the electrical heater.

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    When the Heater Motor Runs Slowly or 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 checked for physical blockage—the power supply and the heater power requirements may be mismatched.

    240 V Heater Attached to a 120 V Circuit

    If this is the case, the heater might run but its output will be greatly degraded. 

    Correct by removing the existing heater and installing a new heater suited for 240 V. 

    120 V Heater Attached to a 240 V Circuit

    In this scenario, a great amount of power is flowing into a lower power heater. This will likely cause the heater to fail and maybe even cause a fire.

    Shut off the circuit breaker immediately. Remove the existing heater and replace it with an appropriately sized heater.