If your furnace is blowing out cold air, there could be several reasons why this happening. Let’s look at the common causes and what homeowners can do to fix any issues with their furnace.
Reasons Why Your Furnace Is Blowing Cold Air
Below is a list of several common reasons why your furnace may be blowing cold air instead of warm air. Thankfully, there are a few things all homeowners can do to both solve and prevent these issues.
1. Wrong Fan Settings
Always start with the easiest solution whenever troubleshooting. In this case, it’s best to start with the thermostat fan setting. Start by seeing if the fan is set to ‘On.’ If it is, air will blow consistently, whether or not your furnace is producing heat.
If the furnace always blows warm and cool air, then it is likely an issue with the fan setting. This is more common with older thermostats featuring a physical fan control switch. The older switches can be bumped easily.
In this case, the fix is fortunately quite easy. Start by moving the setting from ‘On’ to ‘Auto’. This should resolve the issue quickly.
2. Dirty Flame Sensor
If the gas furnace is blowing cold air, followed by an abrupt cut off, the flame sensor could be the culprit. When the furnace cycles up but the sensor does not detect the flame’s heat, it will shut down the furnace in order to prevent the gas from entering the home.
The flame sensor is a crucial safety component, but it can collect an excessive amount of debris on its surface. If this happens, it will set off a false alarm, which ends the cycle prior to the circulating air going from cold to warm.
Thankfully, there is an easy fix to this situation. Turn the furnace’s power off and remove the flame sensor. Next, clean the sensor completely by using either a fine steel wool or an emery cloth. Always clean it lightly, scraping along its surface. Refrain from using a coarse grit sandpaper. After the furnace is back up and running, purchase a replacement sensor.
3. Dirty Filter
A clogged furnace filter can result in the furnace or heat pump completing a full cycle without the air warming up enough. Contrary to most homeowner’s beliefs, with a furnace, the blower can still push air through the vents.
The blower draws air through the path of least resistance, which is typically through any gap in the furnace or vent system. Always check to see if the filter needs to be replaced. Filters need to be inspected and replaced regularly.
4. Issues With Ignitor Or Pilot Light
Gas furnaces feature an ignitor or pilot light in order to spark natural gas into flame. Whenever the pilot light fails, the heat will not be triggered. Instead, the furnace will circulate cold air until the unit recognizes the issue and shuts down.
At this time, homeowners should notice a steady flow of cold air, followed by an abrupt stop. Newer furnaces use a solid-surface igniter that raises the temperature enough to engage the natural gas.
If your furnace has a faulty igniter, it must be replaced. A pilot light may simply need to be cleaned and relit.
5. Fuel Problems
It is quite possible that your gas furnace refuses to heat because it is getting an improper supply of gas. In this scenario, the furnace would blow cold air and shut down. Make sure the shut-off valves are open at this time.
If there is still no gas reaching your furnace, it could be a sign of an issue within the system. While you can troubleshoot gas lines, this repair is best left to the HVAC professionals.
An electric furnace may blow warm air if any of the heating components fail.
6. Condensate Line Is Clogged
High-efficiency gas furnaces will have a condensate line. This line is designed to allow excess water produced by the furnace and AC to drain away from the unit.
The water will back up whenever there is dirt or debris obstructing the line. This ultimately triggers a shut-off safety switch. At this time, the furnace may not light, blowing only cold air, followed by a quick shut down.
Conclusion
Whether you are taking on some common problems or simply performing routine maintenance, it’s essential to keep your furnace clean. For more information, contact the experienced HVAC team at Tru Comfort today!
Tru Comfort Heating & Cooling In Anthem, AZ
At Tru Comfort Heating & Cooling, we deliver reliable, efficient, and cost-effective solutions to enhance comfort and water quality. Whether you need HVAC installation, repair, maintenance, or water treatment solutions, our team is here to assist you every step of the way. Contact us today for exceptional service from an insured and bonded HVAC company. Experience reliable and efficient solutions that exceed your expectations.
