Why is My Furnace Not Blowing Hot Air?

Your furnace is running like usual, but you are now noticing there is no hot air at all.

What caused this to happen?

The simple answer is: It depends on your situation

But what we can do is share our knowledge about this problem, some repairs can be done yourself, but other scenarios need to be inspected and repaired by a professional.

American Comfort One Hour Heating and Air Conditioning can help you get your furnace back to standard.

Start By Checking The Thermostat

Check for these symptoms

  • Cold air
  • Fan is constantly running

A good place to start is the thermostat. If your thermostat’s fan setting is set to ON, then your furnace blower will constantly be operating even when it is not putting warm air into your home. The cold air you feel is from the fan blowing it in.

To fix this issue, just flip the fan switch from “ON” to “AUTO.” The auto setting will tell the furnace to only blow warm air into your home when the furnace is on.

Overheating Furnace 

Furnace overheating can be the cause of your cold air dilemma and this is caused by having a dirty filter. The dirty air filter is blocking the airflow, causing the furnace to run longer when heating your home. This process causes your furnace to overheat.

It is important to note that constant overheating can damage your heat exchanger. When the problem reaches the heat exchanger, then it is time for a new furnace.

Problem With The Pilot Light Being Out

  • Relight the pilot light – instructions on how to do this is located on the furnace or in the manual
  • Check to see if the furnace’s gas valve switch is on
  • Clean the pilot light
  • Replace the thermocouple

You can replace the thermocouple yourself by buying a replacement at any home improvement store. But, if you are not familiar with how to do this then consult a professional technician.

Problem With The Flame Sensor

If the flame sensor is dirty this will cause your furnace to cycle and off.

Lacking Gas Supply

The gas supply to your furnace has been cut off, the system might even shut itself down for safety measures if this is the issue.

Clogged Condensate Drain Lines

Clogged condensate drains prevent the furnace from lighting.

Damaged Ducts

Your warm air goes through the ducts, but if your ventilation has holes in them they will let cold air come in contact with the air being blown into your home.

Wrong Sized Furnace

If your furnace is improperly fitted for your home then that can be why your home has cold air. Furnaces too small cannot effectively heat your whole home. Furnaces too big will cycle on and off. Lack of power or a confusion in the mechanics is your problem here.

The cold air blowing in your home is not good and the problems can vary. If your furnace is the wrong size then you will need to get a new furnace. An HVAC technician can help you with the sizing.

Call: (847) 296-3444 for Furnace Repair and Replacements

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