When it comes to conventional gas furnaces, it isn’t very hard to trace down the issue but it often takes a professional to repair it. Whether your home is getting heated inconsistently, constantly or not at all, checking for these common issues can help you determine what’s wrong and how you can fix it. Many of the issues below can be caused by a faulty thermostat, but it’s important to rule out potential mechanical issues before replacing the thermostat.
How Forced-Air Furnaces Work
Forced air furnaces function by pulling cold air into the ductwork, cleaning it with an air filter, heating it up and pushing it back out into the vents throughout the building. Read on to learn about eight common issues with gas furnaces!
No Heat or Insufficient Heat
When a gas furnace is providing no heat or insufficient heat, you may have a clogged air filter, no power to your furnace, or the wrong size furnace for the space. A properly sized furnace is crucial to maintaining the desired temperature(s) of your space.
Furnace Frequently Cycles On and Off
If you’ve heard your furnace cycle on and off more frequently than usual, check if the exhaust vent or filter are blocked. You could also have improper airflow, so investigate all possible options before replacing parts to save yourself time and money.
Blower Runs Constantly
If your blower is constantly running, the fan setting is likely on, meaning your furnace is continuously blowing unheated air through the ductwork. Turning off this setting will often fix it, but if that doesn’t work, you may have a problem with the limit switch that monitors the internal temperature of the furnace, which you’ll need a professional to replace for you.
Furnace Is Noisy
Noisy furnaces are not only annoying, but they can indicate mechanical issues. If you hear abnormal rumbling, squeaking, rattling or humming, you should look at the mechanical components of your gas furnace to make sure everything is working, as well as check the condition and lubrication of your blower motor.
Pilot Light Is Out
The simplest fix to a pilot light that’s gone out is relighting it, but if that doesn’t fix your furnace issues, you may need to replace the thermocouple. You can learn how to test if your thermocouple is faulty here!
Electronic Ignition Is Failing
If your electronic ignition is failing, your furnace won’t have a source of heat. Most modern furnaces have intermittent pilot lights or hot-surface ignition systems, which light the main burners when the thermostat calls for heat. If you have a failing electronic ignition, have it resolved by a professional.
Thermostat and Furnace Are Mismatched
Thermostat Is Faulty
If you’re having issues with temperature regulation in your home, you may have a faulty thermostat. Before replacing it, rule out issues with the furnace itself as discussed above. Check the power to your thermostat and make sure it’s free from dust and debris. If you have power to the thermostat and the rest of the furnace is functioning normally, you may have a faulty thermostat.
If you have–or think you may have–any of the above issues, clean your air filter, check for power to your furnace and thermostat and call in a professional to deal with the rest.