Gas Furnace Not Working? Here's How To Easily Reset It
Is your gas furnace not starting up or running properly? Don't panic - trying resetting it yourself before calling an HVAC technician. Resetting a gas furnace is an easy do-it-yourself task that can get your heat back up and running.
Resetting your furnace involves cycling the power, gas supply, and pilot light. It clears out any built up gas and restarts the ignition sequence. Oftentimes, this simple repair can fix minor glitches that prevent the furnace from starting. Read on to learn how to troubleshoot and reset your gas furnace to get your heat working again.
Step 1 - Check the Breaker Panel
First, check the electrical breaker panel and locate the circuit breaker controlling the furnace. Make sure it is switched to the ON position. Furnaces require electrical power to operate the fan, ignition, valves, and controls. If the breaker has tripped, try resetting it fully to the OFF position and back ON.
What to do if the breaker is tripped
If the furnace breaker repeatedly trips, this indicates a short circuit or other electrical issue. Check the furnace wiring for damage. You may need to call an electrician if you cannot find the source of the short circuit. Never override or bypass a tripped breaker - this is an important safety mechanism.
Step 2 - Turn Off the Furnace
After verifying the furnace has power, locate the furnace power switch on the control board. Turn it to the OFF position. There may also be an external shut-off switch near the furnace you can switch off. The furnace must be turned off before proceeding with the reset steps.
Step 3 - Turn Off the Gas Supply
Next, locate the gas supply valve on or near the furnace and turn it clockwise to the OFF position. This will stop the flow of gas to the furnace burners. It's typically a red shut-off valve on the gas supply pipe. Turning it 90 degrees until it's perpendicular to the pipe completely cuts off gas flow.
Waiting for the gas to dissipate
After shutting the gas valve, wait at least 5 minutes for any accumulated gas to dissipate. This crucial safety step prevents the risk of an explosion. Do not attempt to relight the pilot or power on the furnace until the gas has had time to fully clear.
Step 4 - Ignite the Pilot Light
If your furnace has a standing pilot light, it must be manually relit using a long lighter after resetting the furnace. Use a long barbecue lighter to reach the pilot light assembly located on the burner. Depress the gas valve while lighting to bleed any air out of the line. Hold the lighter to the pilot assembly for about 60 seconds to heat the thermocouple until the pilot stays lit.
If the pilot won't stay lit
If the pilot light repeatedly goes out after lighting, the thermocouple may need replacement. The thermocouple tells the gas valve when the pilot is lit. Try cleaning any corrosion off of it with an emery cloth. If that fails, technicians can replace the thermocouple.
Step 5 - Restart Automatic Ignition Furnaces
For furnaces with electronic ignition, there's no pilot light. Turn the furnace power switch back to ON once the gas is fully off. The hot surface igniter will heat up to 900degF to ignite the burners automatically. The startup sequence may take a couple tries - allow it to complete its cycle.
If the furnace won't ignite
If an electronic ignition furnace fails to start consistently, inspect the flame sensor. This detects ignition. Clean any dirt or corrosion off with steel wool. Check for flashing error codes on the control panel pointing to faults. Have a professional assess it if faults persist after cleaning.
Step 6 - Restore the Gas Supply
After the furnace successfully starts, reopen the gas valve by turning it counter-clockwise. Verify that there are no leaks at any of the gas connections using a soapy water solution. Bubbles will appear if leaks are present. Tighten fittings or have a technician repair leaks immediately.
Step 7 - Replace the Furnace Cover
Finally, replace the outer furnace cover and panels that were removed during the reset process. Never operate a furnace without proper covers and blower doors in place. Exposed electrical contacts and moving parts present serious hazards.
Additional Furnace Reset Tips
Beyond cycling the power and gas, here are some additional maintenance tips when resetting your furnace:
- Check the air filter - Replace if dirty
- Inspect the blower motor and belt
- Monitor the flame color - Should burn blue
- Consider professional annual tune-ups
Resetting your furnace before calling for costly repairs can resolve many startup issues. However, if your furnace fails to operate correctly after resetting it, contact a professional HVAC technician for service. An annual tune-up will help keep your system running reliably.
Resetting a gas furnace is a straightforward DIY process that often gets the heat working again. Try these troubleshooting steps first before panic sets in. Just remember to exercise caution and follow safety procedures when working with gas appliances. With some simple maintenance and a reset when needed, your furnace can continue providing cozy warmth for years to come!