- 5 January 2021
Picture this: On a sub-zero Georgetown winter day, your furnace is suddenly blowing cold air instead of warm. Yikes! That’s the last thing you need. Why is it happening, and what can you do to make it stop?
1. Thermostat Settings May Need Adjustment
The cause may actually be quite simple: an incorrect thermostat setting. If you check the thermostat and it’s set to “ON,” the furnace fan will constantly run, even when the furnace cycles off. At these times, the fan will be circulating air which is room temperature, rather than the cozy warm air you expect.
SOLUTION: Simply switch the thermostat settings to “AUTO.”
2. Other Thermostat Issues
Some older thermostats are not hardwired to your home electrical system. If you run into an issue, it may be that the battery is running down. For problems with a new thermostat that you installed yourself, the thermostat might not be the correct type for your heating system.
SOLUTION: Replace a rundown battery. For an incompatible thermostat, consult an HVAC professional.
3. Dirty Air Filter
Your furnace filter must be changed (or cleaned) regularly. If this is not done every three months or so, it will become clogged, reducing airflow to your furnace. Any overly restricted airflow will cause the furnace safety control (“limiter switch”) to shut down the burners. Because the burners are no longer producing heat, the air coming from your furnace will become cold.
SOLUTION: Change or clean the filter and reset your furnace safety control according to the manufacturer’s directions.
4. Clogged Condensate Line
Today’s high-efficiency furnaces are equipped with a line to drain off condensate, produced as a byproduct of the heating process. When the condensate drain line is clogged, your furnace will blow only cold air.
SOLUTION: Have a knowledgeable heating and cooling tech clean your condensate line.
5. Pilot Light Is Out
In a gas furnace, the pilot light may have simply blown out. Or, perhaps it’s not lighting properly. This is usually due to either dirt and debris in the pilot light itself or could be an issue with your thermocouple.
SOLUTION: You can try to relight the pilot light yourself, carefully following the manufacturer’s instructions. But if it goes out after a minute or two – or won’t light at all – call for expert help.
6. Insufficient Gas Supply
Your furnace will not work, and blow the hot air you’d like, without adequate natural gas. If you’re sure that your gas valve is open and the supply hasn’t been turned off, you could have a blockage in the gas line.
SOLUTION: Ask a heating pro to inspect the line and troubleshoot the problem. This is not a DIY fix!
7. Leaky Ducts
Wear and tear on your ductwork may eventually cause it to leak due to cracking, detaching, or other damage. This leakage allows warmed air to escape and cold air to take its place. The cold air coming from areas like your attic or crawlspace gives you the impression that your furnace is blowing cold air.
SOLUTION: Have your ducts professionally sealed.
Here To Improve Your Home Comfort
If your furnace is blowing cold air or malfunctioning in any other way, contact Appleby Home Comfort. We are your friendly experts for furnace repair or replacement in the Georgetown area. Your home comfort is our priority!