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How to Reset Power If Your Furnace Won’t Turn On

by vscontent on January 19, 2018

How to Reset Tripped Breaker Replace Blown FuseIf your furnace won’t turn on, check the power first. Your HVAC system is hooked up to the electric system. Check the main fuse box or circuit breaker and make sure the furnace master switch is on.

Electrical Panels: Circuit Breaker vs Fuse Box 

Although you probably have an electrical panel and not a fuse box, it’s a good idea to know the difference.

If you have black switches, it’s a circuit breaker box. If you have knobs and fuses, it’s a fuse box. Make sure you have extra fuses near the panel for quick and easy replacements. To find fuse replacements, simply take one of your existing fuses to the local home improvement store and purchase replacements of the exact size and type.

Furnace Switches

All heating equipment, including furnaces, boilers, heat pumps, and space heaters should have an off/on switch.

The master switch should be very close to the unit itself. Make sure it is flipped on.

You may also have an emergency off switch located outside of the basement area, ostensibly so someone can turn off power without having to enter a dangerous situation.

Make sure both switches are on. If flipping the switches on does not restore power to the furnace, turn them both off and head for the circuit breaker.

How to Reset a Circuit Breaker

HVAC systems should be on their own 240-volt dedicated circuit. If they are not, contact a service technician right away.

During normal operation, your furnace should not be tripping the breaker. The number one reason for why this might happen is an overworked blower motor. Dirty air filters, clogged condenser units, air leaks, and blocked vents/registers can all contribute to this. Learn more furnace troubleshooting tips.

So, you’ve overloaded the circuit and tripped a breaker. The breakers in your electrical panel will trip as a safety precaution if the demand exceeds the supply of the circuit. If this happens more than once, contact a professional HVAC technician.

To safely reset a tripped breaker:

  1. Turn off the furnace master switches to the off position. If it’s not the furnace, turned off or unplug all of the devices that are part of the circuit.
  2. For safety reasons, make sure you are wearing shoes, completely dry, and work with one hand only. Put your other hand in your pocket or holding on to a non-metal flashlight.
  3. Find the main electrical panel, open it up, and look for the tripped breaker (normally in the “off” position or in a “neutral” position somewhere in between “on” and “off.” The HVAC system should have its own 240-volt dedicated circuit.
  4. In order to reset the tripped breaker, you must first switch it to the complete “off” position before forcefully flipping it back on.

If this does not restore power to the room/circuit, don’t try any further electrical exploration. Contact a service professional to troubleshoot the problem.

How to Replace a Fuse

  • Contact a professional if you have any doubts.
  • Use one hand only.
  • It is dangerous to replace a fuse with one that has a different amperage rating.
  • Make sure you have the right fuse (same thread size and amperage).
  • Shut off any plugged-in devices.
  • Turn off the main power switch.
  • Unscrew the blown fuse. Keep in mind, you may need a special adapter to unscrew the fuse.
  • Screw in the replacement fuse.

If resetting power at the electrical panel does not work, contact a professional technician to investigate the electrical connections between you service panel and the thermostat and heating system.

Safety Warning

Remember, your electrical panel acts as a safety mechanism. For safety reasons, you should investigate why the circuit blew. Check air filters, proper airflow, and blocked vents.

If you trip the breaker or blow a fuse more than once in a short period of time, contact a professional right away. This can be a sign of a fire hazard.

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The expert technicians at Pacific Heating & Cooling can troubleshoot your heat pump and make the necessary repair on-the-spot. Contact us today for 24/7 service.

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