A furnace blowing cold air is clearly a bad sign, but don’t assume the worst just yet. This issue may occur for many reasons, so let’s explore a few common causes — and how you might be able to fix them.
The Thermostat Is Faulty
Whenever you have an HVAC issue, it’s best to rule out the simple things first. If you’re only getting cold air from your vents, double-check your thermostat and verify it’s in heating mode. In addition, make sure your fan is set to “Auto” instead of “On.” This will ensure your fan only runs when heat is being produced, preventing cold air from circulating through your home. It’s also possible the thermostat itself may need repairs, especially if you’ve noticed other signs of trouble.
The Ignition System Is Bad
Since furnaces burn fuel to generate heat, they require a working ignition source to function properly. Modern units typically have electronic ignitions, which are too complex and risky for DIY repairs. If you’ve had your system for a while, however, you may be in luck. Many older furnaces use pilot lights, which can be safely relit by following the steps in the system’s manual. If the pilot light goes out again, don’t continue relighting it. This is a sign of a bigger problem that likely requires expert attention.
The Air Filter Is Clogged
Ironically, a loss of heating is a common sign that your furnace itself may be getting too hot. Dust can easily clog air filters and create obstructions that reduce airflow within your system, especially without routine maintenance. This forces your furnace to work even harder, causing internal components to begin overheating. Eventually, the burner will automatically shut off and stop producing heat. To prevent this, be sure to check your air filter regularly and replace it at least every three months.
If your home heating system has suddenly gone cold, call the pros at Air Specialists Heating & Air Conditioning, Inc. We offer expert diagnostics and highly responsive furnace repairs, including a 100 percent satisfaction guarantee throughout the Quincy, IL and Hannibal, MO areas.
