3 Reasons Why Your Furnace Is Blowing Cold Air

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Furnace Blowing Cold Air?

A furnace that is not working correctly can be a source of great frustration to homeowners. You know you have a serious issue with your system when it starts blowing cold air. It is a problem that must be looked at in a timely manner to avoid incurring costly repairs that could result from ignoring the problem. The ideal way of knowing the cause of the problem is to contact your HVAC service provider who can quickly troubleshoot the issue and get busy on correcting it.

Below we explain some of the common causes and probable causes for your furnace to start blowing cold air.

The Thermostat Is Set to ‘Fan On’

One of the probable reasons for your furnace to blow cold air could be that the thermostat fan setting is set to “on” instead of running on “auto” mode. When on the “on” setting, the fan will be primed to keep running round the clock, whether the system is in a heating cycle or not. You can address this issue by merely setting the thermostat to “auto.” Fan on is a more preferable setting though as it will keep the air moving, as well, reduce the gaps in temperatures between different levels of the home, summer and winter.

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The Furnace has Over Heated

Your furnace shuts off its burners when it starts overheating; however, the fan will keep running, trying to cool the unit. You might experience some warm air, but this soon changes since the burners are off, and the fans are only pushing cold air. The problem can be attributed to dirty air filters, which can either be cleaned or replaced with new ones. If you find the filters are clean, then you should call your heating contractor to inspect your furnace and fix the issue.

Faulty Safety Devices and Sensors

All furnaces have various types of sensors as well as a high limit switch. These components are essential for controlling when the burners and other safety monitors. If any of these parts are faulty, then this will impact the system’s auto-run functions. The fan, for instance, might turn on before the unit is hot, or the burners might turn off while before the heating cycle is complete. Alternatively, the fan might not get the signal to switch off once the heating cycle has ended. As a result, the vent will be throwing cold air into the rooms. Such problems are mostly associated with the sensors and safety devices that a professional can find, examine, and fix.

If you turn on the furnace and it blows cold air for a short while, and then warm air is blown that gets hotter gradually, then there is no reason to worry. The system will have cold air in the ducts whenever your furnace was off or is in-between its heating cycles. It thus must first push out the cold air that is in the ductwork first as it starts up, but the warm air should follow shortly after.

If you have any concerns about your furnace or questions related to your heating system, contact JD Swallow for assistance. We are experienced and reputable heating contractors serving Ottawa and the surrounding areas. Contact us for all your heating related issues, be it maintenance services, repairs, or new installations.

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