How To Restore Power If Your Heater Trips The Breaker (Or Fuse)

If your furnace or heater won’t turn on, there are a couple of things you should check first before calling the pros:

  1. Thermostat setting and batteries
  2. Clean air filter and closed access panel
  3. Pilot light and gas valve
  4. Furnace switch and electrical panel (circuit breaker/fuse box)

Even though your furnace runs on fuel, such as natural gas, propane, or oil, many of the components rely on electricity to communicate with each other. If power to your furnace has been cut off, you will need to restore it before your furnace can turn on.

Learn more furnace troubleshooting steps.

How to Restore Power to Your Furnace

  1. Check Thermostat & Power Switch

Before heading to your circuit breaker or fuse box, make sure the thermostat is on “heat” and the furnace power switch is turned on.

Source: Jenn Durfey (flickr)

Look for an electrical switch near your furnace. Sometimes, the furnace won’t turn on because somebody accidentally mistook the switch for a light switch and turned it off.

If the switch is in the “on” position and your thermostat is set to “heat” and a higher temperature than room temperature, the next step is to find your electrical panel.

  1. Locate Electrical Panel

Hopefully, you already know where your electrical panel is and whether or not you have a fuse box or circuit breaker. If not, try looking in your basement, garage, or a closet. It is normally located in a grey metal box. Consult your home inspection papers or contact the local electrical company if you cannot find it.

  1. Reset the Circuit Breaker

Most homes will use circuits rather than fuses. When you locate the circuit breaker box, you will notice multiple rows of circuit breakers with one big breaker near the top. The top circuit breaker controls power to the entire house. The circuit breakers below are connected to individual rooms (and sometimes individual appliances). Your HVAC system probably has its own dedicated circuit.

The switches should be labeled, but if they aren’t, it should be pretty easy to tell which one is the tripped breaker. The tripped breaker will be in a different position from all the rest. If your switches aren’t labeled, spend some time with a partner flipping the switches to determine which parts of the home they are connected to.

How to reset a circuit breaker:

First make sure your hands and feet are completely dry. Only use one hand to flip the tripped breaker.

  1. Locate your electrical panel, open up the cabinet door, and look for any breakers that look different from the rest. The tripped breaker could be in the “off” position (opposite direction of all the other breakers) or it could somewhere in the middle of “off” and “on.”
  2. In order to restore power, first move the position of the tripped breaker all the way to the “off” position before flipping it back on.

This should restore power. If you have tried to flip the breaker back on, but the outdoor unit still won’t turn on, you may have an outdoor power switch that has been turned off.

Go outside a look for any power boxes near your unit. You may have a switch, lever, or fuse that is in a separate box near your outdoor condenser unit.

  1. Replace a Blown Fuse

Unlike a circuit breaker, fuses must be replaced when they blow.

How to fix a blown fuse:

  1. Locate your fuse box and look for the blown fuse. It is normally discolored, cloudy, or has a piece of broken or melted metal inside.
  2. Once you know where your broken fuse is, unscrew it and throw it away.
  3. Replace your broken fuse with a new one that is the exact same size, type, and amperage. Double-check that the replacement fuse matches the amperage rating of the circuit.

Keep fuse replacements on hand so you don’t have to go to the store. To find an exact replacement, take your fuse to the local home improvement store and ask for the exact same type.


If your circuit breakers are tripping on a regular basis, however, you may have a deeper electrical issue at hand. Common reasons include too much electrical demand, a fallen power line, or a malfunctioning appliance. The experts at Service Champions will be able to tell you why your electrical panel continues to trip.

If these furnace troubleshooting steps won’t restore heat, rely on our service professionals. Contact Service Champions today for expert furnace and heater repair, maintenance, and troubleshooting. We are your reliable HVAC experts for Northern California.

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