When winter is finally here and the chilly weather becomes unbearable, the first thing you do is turn on your furnace. But sometimes things don’t work as you expect. Instead of your furnace blowing the desired warm air, it blows cold air. It’s frustrating to have to deal with such malfunctions at a time when you need your unit most. But why would the furnace blow cold air? Here are possible reasons.
1. Thermostat Setting
Before going to anything else, check the thermostat setting. Check whether the unit fan is set to ON or AUTO. If your thermostat is on, the fan will continue running but will blow cold air. Switch it to auto so it goes back to heating the air.
2. Pilot Light Is Out
Older furnaces come with a pilot light that should run throughout to light the burners. But this flame sometimes goes off, and you’re supposed to relight it. Don’t check for this issue if you have modern furnaces because they have electric ignition which doesn’t go off.
3. No Gas
Your furnace needs enough gas to produce the required heat. You should ensure your furnace has a consistent gas supply to heat the air. Check if this is the case by confirming if the gas valve is on. If the valve is off, then it’s time to do the recharge.
4. Clogged Air Filter
Air filters get dirt accumulation over time and end up clogging. When it clogs, it will restrict enough airflow causing the furnace to work harder and overheat. An overheated furnace will keep running but supply cold air. Replace the dirty air filter to restore smooth airflow.
5. Leaking Ducts
Have you been following your HVAC maintenance schedule? A maintenance schedule helps to keep your system running effectively all year round.
If you’re not serious with maintenance, then leaking ducts is a scenario you’re likely to encounter.
Your HVAC could be blowing cold air because there are holes in the ductwork. Heat energy escapes through the holes to the extent that the air is cold when reaching your living areas.
Hire an HVAC expert to identify and close the leaks to stop further heat loss.
6. Dirty Flame Sensor
A pilotless furnace uses a flame sensor to keep the furnace working once it’s turned on. If the flame sensor is dirty, the furnace will not produce heat for a long time. It will turn cold quickly.
If you understand how a furnace works, you can clean the flame sensor yourself. Otherwise, get the services of an expert to fix the issue.
7. Overheated Furnace
The part of the furnace responsible for heating the air is the heat exchanger. It’s made up of metal coils that are heated, and in turn, heats the air passing over it. Sometimes the heats exchanger will overheat. The furnace reacts by turning off the burners but keeps the fan blowing to cool down the exchanger. At this point, you’re likely to feel the vents blowing out cold air.
There are various reasons why the heat exchanger is overheating. One of them is limited air supply over the metal coils. Limited airflow is likely to be caused by a clogged air filter. If it’s clogged, it will not allow enough air to pass to stop the heat exchanger from overheating.
You can consider cleaning or replacing the air filter to solve the problem.
If the furnace continues to blow cold air after fixing the air filter issues, then it’s time to call an expert. An overheating heat exchanger is a problem you’d want to resolve immediately. A pro will get the job done to your expectation.
8. Furnace Just Turned ON
If the furnace has been off for a long time, it’s normal if it blows cold air in the first few minutes. At this point, you have no reason to worry. Give it some time to see if the air starts getting hot. If there is no change after 10 minutes, you’re possibly facing a bigger issue. Call an expert to look into the issue.
Still Having Problems?
For minor furnace problems, the above troubleshooting methods should solve the problem. But if none of the solutions seems to work out, then your furnace might be having a bigger issue that needs professional expertise. Don’t attempt to troubleshoot further as you might damage the furnace.
If you reside in Serving Frederick, MD, and surrounding cities, call Weather Masters Corp. professionals to come to check your furnace. We excel at providing quality heating and cooling services to restore your home’s comfort. We can also service boilers.