Gas furnace troubleshooting can be tricky or confusing for those of us unfamiliar with the parts or working of such an appliance. If you have the furnace turned on and still experience a winter chill, there are some basic steps you can take to diagnose the problem and find a remedy.
If the furnace is turned on and does not provide heat, the first place to check is the thermostat. Ensure it is set to the correct level. If the temperature setting is too low, you have an easy solution—turn up the thermostat. If the temperature setting is correct, check if the thermostat is working. If it does not seem to respond, shift the dials around a bit to see if it works. If you have a programmable thermostat, check the batteries to see if they need replacement. Also check to see if the furnace switch is turned on.
Electrical and Vent Problems
If it still does not work, it could be because of electrical problems such as a blown fuse or a tripped circuit breaker. Check for these issues and repair as necessary. Frequent problems leading to blown fuses or tripped circuit breakers will have to be assessed by a qualified electrician. Other minor causes of heat impediments are dirty ducts, vents and furnace filters. Clean the vents and ducts in your home to ensure good air flow. Clean or replace the furnace filter as required.
Pilot Light and Outdoor Vent Blocks
Ensure the gas supply is turned on. If your furnace uses a pilot light, check to see it is lit. The pilot light can go out if there is a draft. Relight the pilot light by following the instructions on the furnace. If the pilot light goes out repeatedly, there may be a blockage clogging the opening. After turning off the gas, use a thin wire to clean the opening. Check the outdoor furnace vents to ensure there is no blockage because of ice. Removing such blockage should restore the furnace to working condition. Remember to turn off the furnace before removing any such impediments.
Burner Issues and Gas Leaks
Burner problems can also cause inefficient heating. The flame must be even and must not show any trace of yellow. To clean dirty burners or to adjust the flame level, you must call a qualified professional. Find out if there is a gas leak by applying a soapy solution on the connections of the gas supply line. If it bubbles, there is a gas leak. Call a licensed gas technician for help.
If the furnace turns on and off repeatedly, it could because of a problem with the blower motor. Oil the ports on the ends of the blower motor shafts. Ensure the belt is not too loose or tight, and adjust as needed. If the belt is old and worn out, you must replace it. If the blower runs constantly, check to see if the fan switch is on the proper setting, and is not set on continuous circulation mode.