Furnace Blows Cold Air? Here’s What Could Be Going On
Your furnace kicks on, the blower starts moving air… but it’s cold. Don’t panic — this is a common call our technicians at Mechanical Extremes receive, especially when temperatures drop. Here are a few likely causes.
- Dirty Air Filter
The most frequent culprit is also the simplest to fix. A clogged filter restricts airflow, causing the furnace to overheat and shut off the burners for safety. When that happens, the blower continues running, pushing unheated air through the vents.
- Rollout or Limit Switch Tripped
Modern furnaces include safety switches that shut down the burners if overheating or flame rollout is detected. Rollout can result from poor combustion, blocked vents, or other system issues. If this switch trips repeatedly, it needs professional attention.
- Improper Gas Pressure
If gas outlet pressure isn’t within specifications, your burners may fail to ignite or stay lit. That leaves the blower running with no heat being produced – a job for a qualified technician with proper testing equipment.
- Ignition or Flame Sensor Issues
When ignition components or flame sensors get dirty or fail, the burners may light briefly and then shut down. The blower may still runs its cycle, blowing cool air instead of warm.
When to Call the Pros
A quick filter change might fix the problem — but repeated cold-air cycles usually signal a deeper issue. Mechanical Extremes can inspect your system, pinpoint the cause, and restore dependable heat fast.
Stay warm, stay safe — call Mechanical Extremes when your furnace stops producing heat.
(517) 812-2484
