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What to Do If Your Furnace Blows Cold Air
The Comfort Company
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What to Do If Your Furnace Blows Cold Air

Your furnace is running, but for some odd reason, it suddenly started blowing cold air rather than heating your home. What should you do? And more importantly, what on earth is going on?

Before you call a furnace repair specialist for help, there are a few simple fixes you can easily try out on your own to see if you can solve the problem.

Read on to learn what might be causing your furnace issues and what you can do to troubleshoot a heating system that blows cold air.

Check Your Thermostat

If your furnace randomly starts blowing cold air, there’s always a chance your thermostat setting is to blame. Make sure your thermostat is set to “heat,” and ensure the temperature setting is high enough for the furnace to turn on.

You’ll also want to check the blower setting to see if it’s set to “on” or “auto.” When the blower is set to “on,” it will continue blowing air even when the furnace isn’t running. Keeping that setting on “auto” will ensure the blower only functions when the furnace is actively heating air.

The thermostat itself could also be the culprit. If your temperature and blower settings appear to be fine, you may simply need to replace your thermostat.

Check the Pilot Light 

Do you have an older furnace? If so, the pilot light may have been extinguished, and if that little flame isn’t burning, your furnace won’t get hot. Newer furnaces — those that were manufactured after the year 2000 — don’t have continuously burning pilot lights, so if you have a more modern unit, the pilot isn’t your problem.

If you need to relight your pilot light, refer to the appliance’s directions, which are likely located somewhere on the unit. If you relight the pilot and the flame continues to go out, the issue is likely caused by a faulty thermocouple. You’ll need to call a furnace repair specialist to test and repair this component.

Examine the Flame Sensor

If your furnace doesn’t have a pilot light, it likely has a flame sensor. That sensor is a safety mechanism that ensures the unit heats to the appropriate temperature and prevents the buildup of hazardous gas when a flame is not present.

However, when that sensor is dirty, it’s designed to automatically cause the burner to shut down because it cannot detect a flame. Consequently, your furnace may blow cold air continually and quickly cycle between warm and cold.

You can quickly remedy this issue by cleaning the flame sensor. If that doesn’t work, the component will need to be replaced. If you’re unsure how to do either of these things, hire a furnace repair expert to handle the job.

Is your flame sensor dirty because you’ve neglected your furnace? If so, you’ll want to brush up on what every homeowner should know about furnace maintenance.

Swap Out Your Filter

A filthy filter can easily restrict airflow to your furnace, which will force the unit to run longer than necessary to heat your home. Eventually, it’ll overheat, shut down, and stop producing warm air altogether.

The fix for this issue is quite simple: Swap out the dirty filter for a clean one. Your furnace probably won’t start blowing warm air right away, but it should in a few hours. If the unit still blows cold, call a furnace repair specialist who can inspect and diagnose it.

If you’re unsure how to find a reputable heating and cooling specialist, you’ll definitely want to check out 5 Signs of a Trustworthy HVAC Company.

Need Furnace Repairs Near Duluth?

If your furnace is acting up, don’t hesitate to reach out to our team at The Comfort Company for help! We specialize in a variety of HVAC services for homeowners in Hermantown, Duluth, and the surrounding areas, and we can help you improve your indoor air quality, too.

To learn more or schedule service, give us a call today at 218-491-1226 or request an estimate, and we’ll be in touch.

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