Below are seven possible reasons your furnace may be blowing cold air:
Many of these issues can be handled with simple maintenance, while others may require professional furnace service.
1. Incorrect Thermostat Settings
Your thermostat is always the first place to check. If your furnace is blowing cool air, it may be set incorrectly—perhaps left on a summer setting. Adjusting it back to heating mode could quickly resolve the issue.
2. Dirty Furnace Filter
Air filters capture dust, soot, and other particles, but when they become clogged, airflow is restricted. This can cause the furnace to overheat and even extinguish the pilot light.
Older furnaces with a standing pilot light may lose their flame with just a draft of air. If you’re comfortable relighting it, you can try doing so yourself. Otherwise, it’s best to call a professional for furnace repair in Bountiful, UT.
3. Gas Valve Problems
If the pilot won’t light at all, the gas valve may be faulty or stuck due to dirt buildup. In this case, have your furnace cleaned and inspected by a licensed HVAC technician.
4. Faulty Thermocouple
If your pilot light ignites but won’t stay lit, a malfunctioning thermocouple could be the issue. This small sensor controls the gas valve and ignition. A technician can easily adjust or replace it to restore proper function.
5. Malfunctioning Electronic Ignition
Modern furnaces with electronic ignition—such as hot surface igniters or intermittent pilots—sometimes fail due to worn parts or misalignment. These problems require professional diagnosis and repair.
6. Leaking Ductwork
Even if your furnace is heating properly, holes or leaks in your duct system can cause warm air to escape before reaching your rooms. This results in cool air blowing through your vents. An HVAC expert can inspect and seal your ducts to solve the problem.
7. Dirty Flame Sensor
If your furnace keeps shutting off shortly after starting, a dirty flame sensor may be to blame. This prevents the gas burner from staying lit and can be resolved with a simple cleaning or replacement.
Looking for a furnace replacement in Layton, UT? Trust Blue Best Plumbing, Heating, Air, & Generators. Our experienced team also provides reliable furnace service in North Salt Lake. Call us today at 801-851-5518 or email service@bluebest.com to schedule affordable, professional heating service.
