In this post, we discuss furnace repair and common furnace issues that you can try to troubleshoot before you have to recall a repair service.
Are you having furnace problems?
If you want to try and troubleshoot common furnace issues first, such as relighting the pilot light, continue reading below.
If you want to call a professional for emergency furnace repair in the Naperville, Warrenville, Carol Stream, Downers Grove, Geneva, Lombard, West Chicago, Batavia region, call us at
Gas Furnace Troubleshooting Issues
- No heat / Not enough heat
- Turns on and off frequently
- Blower does not turn off
- Making too much noise
- Pilot light is out
- Electronic ignition not working
- Thermostat issues
No heat / Not enough heat
No heat or not blowing hot enough air are among the most common reasons that we are called to fix furnaces. On a cold winter day, it won’t take too long to notice when the furnace is not blowing hot air as you need it to.
Troubleshooting furnace not blowing hot air:
- Check that furnace is getting power
- Check fuses and circuit breakers
- Make sure the emergency power switch to your furnace has not been mistakenly turned off
- Try pressing the reset button
- Make sure the furnace cover or door is closed
- Check that the pilot light is on
- Check that heat registers are open
- Check if the flame sensor is dirty
Furnace turns on and off frequently
Troubleshooting furnace that turns on and off frequently:
- Check the thermostat
- Check thermostat is turned to heat
- Check if flame sensors are rusted
- Check if air filters need changing
- Check the heat exchanger
Blower does not turn off
- Check if the thermostat is set to fan continuously
- Check the fan limit control switch
Furnace making too much noise
When your furnace is making too much noise, check these items to try and find the source of the noise:
- Check if blower wheel is loose, broken or out of balance
- Check the motor mount
- Check the transformer
- Check the interior fan
- Check if the power belt is loose
- Check if the power belt needs lubricating
- Check if the metal duct siding is bent or warped
- Check if blower motor needs oil
Check the pilot light
Your pilot light could go out because of a strong draft, dirt and grime around it or dirt in the gas tube.
Relighting your pilot light is usually fairly simple and your owners manual should be able to tell you how.
If the pilot lout is out because of a faulty thermocouple causing the gas supply to shut off, this is less simple and will require you to replace your thermocouple. You may be able to do this yourself or call a professional.
Electronic ignition not working
Many new furnaces do not require a standing pilot light but instead use an electronic ignition system.
- Check that power switch is on
- Check the electronic ignitor. These can wear out.
- Power down your furnace and test the ignition switch
- Check the temperature limiting switch
- Make sure your filters are not dirty and clogged
- Make sure the gas line hasn’t been closed or turned off
The thermostat can be behind a lot of furnace and heating issues. Thermostats can wear out, especially if they were not a good match for your furnace originally. Thermostats need to be carefully selected and are not “mix and match” devices where any will work well with any furnace.
- Check that thermostat has power
- Check that thermostat is set to heat
- Check the batteries in the thermostat
- Check for loose wiring
- Remove the cover and check for dust and grime
Related: Types of Thermostats