The Complete Guide on How to Troubleshoot a Furnace Blowing Cold Air

If you have a furnace blowing cold air, there are certain things you can do. Check out this troubleshooting guide to learn what needs to be done.
A person bundled up in multiple layers of winter clothing, including a hat and scarf, appearing to be feeling cold.

Have you recently turned on your furnace, waited a few minutes for it to warm up only to get cold air blowing?

Numerous problems can cause this.

If you have a furnace blowing cold air, don’t fret! There are things you can do to fix it. Check out this troubleshooting guide to learn what needs to be done!

1. The thermostat

Make sure you check the thermostat is set to the correct setting. If you have a thermostat that has an AUTO and ON feature, make sure the thermostat is set to AUTO.

If it is set to on, this means that the fan will run continuously, and you won’t get heat. Set it back to AUTO, and you’re good.

2. Out of Fuel

If you have a gas-powered furnace, you may have run out of fuel. The pilot light should light the furnace to start the warm air process. If the fuel is not out, your fan will continue to run and not blow warm air out of the vents.

3. Control Board Issues

If your furnace has a control board, there could be a problem with it. If this is the case, try turning off the main switch, wait 30 seconds and turn it back on. The unit may reset itself and may operate as usual on startup.

4. Furnace Overheating

If all you feel is cold air, the problem can be an overheated furnace. Some furnaces have a safety feature if the unit gets too hot to where it can cause a fire, the furnace will shut itself but continue to run the fan.

A block of airflow can cause this. The best thing to check is your air filter. If your air filter is dirty, it will block airflow and can cause your furnace to overheat and shut off.

5. Pilot Light is Out

If you have an older furnace you may have to check your pilot light. When your pilot light goes out, gas will continually run without anything to ignite and warm the air.

Check the manual to the furnace on instructions on how to relight the pilot. If you cannot, it is best to call a professional who works on furnaces to assist with the job.

6. Clogged Oil Filter

If you own an oil-fired furnace, the filter can clog with dirt, debris, or other sediments. When this happens, the clog may interfere with the ignition and can stop the heating process.

7. Bad Duct Work

Your furnace may be blowing cold air due to holes in your ductwork. Hot air will never reach the vent if there are holes in them.

Have your ductwork inspected by a skilled furnace technician to ensure there are no holes or leaks

If You Have a Furnace Blowing Cold Air Have it Checked Out

Preventative maintenance is an excellent way to make sure problems don’t happen in the future.

However, if you are experiencing issues with your furnace blowing cold air, the best thing you can do is have it checked out by a professional.

Luckily for you, though you’re in the right place to do that, so contact us!

Our team is here for you to answer any questions you may have with your faulty furnace.


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