When the temperatures plummet outside, you depend on your furnace to keep your home warm inside. However, there are a number of things that can go wrong with a furnace and cause it not to run, or to run and blow cold air. Here are some possible reasons why your furnace isn't warming your home.
The Filter Is Clogged
When the filter is covered in a mat of dust, hair, and other debris, the airflow through the furnace is restricted. This can cause the furnace to overheat. As a protective measure, the furnace will turn itself off to prevent damage. What may happen is that your furnace will turn on and then turn back off quickly so that your furnace is cycling often but not running for a long duration. The furnace won't be able to heat your home in this situation, but you might be able to solve the problem by putting in a new filter. If that doesn't help, you may need a service technician to clean dust out of the furnace that is causing the same short-cycling problem internally.
The Condensation Drain Line Is Clogged
Another form of clogging that can cause your furnace to shut itself down happens in the condensation drain line. This line moves water away from the furnace so it can drain outside. When the line is blocked, water can back into the furnace or spill onto your floor. When it gets in the furnace, your furnace will shut down to protect itself. If the line has dust or other debris in it, a technician can vacuum the debris out to get rid of the clog so the line drains and your furnace works properly again.
The Thermostat Isn't Working
When your furnace isn't heating your home, one of the first things to check is the thermostat. Make sure the temperature setting is correct and that it is on the auto setting. If the thermostat is placed in the on position instead, the blower runs continuously and part of the time it will blow cold air rather than heated air. Also, change the batteries if that's needed and make sure the thermostat is not near a heat source such as a portable heater that makes the thermostat think your home is warmer than it really is.
A Duct Is Damaged
If a destructive animal such as a raccoon is in your attic, it's possible the animal will rip open a duct to get to warmth. When a duct is pulled apart at a seam or damaged with a rip or hole, then warm air will leak into the attic and cold attic air will mix with the air that comes out of your registers. Depending on the damage, you might be able to patch the leak with duct tape until you can get the duct replaced.
If a quick fix like changing the filter or taping a duct doesn't make a difference, then call a service technician for prompt repairs so you can get your home warm again. There could be problems with the electrical system, blower, heating element, or gas supply that need a trained technician to repair.
For more information, contact companies like Barnetts Heating & Air Conditioning.