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How to Handle a Furnace Blowing Cold Air: Causes and Solutions


Maintenance on a furnace

A furnace is vital for maintaining a warm and comfortable home, especially during the cold winters in Kingston, Ontario. It can be frustrating when your furnace blows cold rather than warm air. Understanding the common causes and how to troubleshoot your furnace can help you quickly resolve the issue and restore warmth to your home.

What Are the Common Causes of a Furnace Blowing Cold Air?

Here are some of the most common causes of a furnace blowing cold air:


Thermostat Issues

If the thermostat is set incorrectly or malfunctioning, it may not signal the furnace to produce heat. 


Solution: Always ensure that your thermostat is set to heat mode and the temperature is higher than the current room temperature. Check the thermostat batteries routinely and replace them if necessary. Recalibrate or replace the thermostat if the problem persists.


Ignition Problems

A malfunctioning pilot light or ignition system can prevent a gas furnace from heating. 


Solution: Ensure that the pilot light is lit. If the pilot light is out, follow the manufacturer's instructions to relight it. For electronic ignition systems, check for error codes or reset the system. If you're unsure or the problem persists, contact a professional technician.


Blocked Air Filters

A dirty air filter restricts airflow, causing the furnace to overheat and shut down as a safety precaution, blowing cold air.


Solution: Inspect the air filter routinely and replace it if it is dirty. Change the air filter every 1-3 months, depending on usage and air quality, to improve the furnace's efficiency.


Overheating Furnace

When the furnace overheats, it triggers a safety limit switch that shuts down the heating element while the blower continues to run, resulting in cold air.


Solution: Check for closed vents or blocked ducts and clear them, ensuring the air filter is clean. If the problem persists, contact a professional technician. 


Leaks in Ductwork

Leaks or holes in the ductwork can cause cold air to blow from the vents as they allow warm air to escape. 


Solution: Routinely inspect the ductwork for visible leaks or damage. Seal the leaks with duct tape or mastic sealant to improve airflow. Hire a professional to examine and repair extensive ductwork issues thoroughly.


Fuel Supply Issues

An insufficient gas supply can prevent a gas furnace from producing heat. Possible reasons for this include a closed gas valve, low gas pressure, or an empty propane tank.


Solution: Open the gas valve and check the gas supply. If you are using propane, ensure that the tank is not empty. If you notice supply issues, contact your gas company. 

Need Help to Troubleshoot Your Furnace? Contact Kingston Home Heating and Air Today!

Kingston Home Heating and Air specializes in HVAC system services and repairs. Our team of trusted professionals will ensure your home is always at the perfect temperature. Want to replace a broken furnace, fireplace, or heat pump? Our experienced team has you covered. Take action to maintain, repair, and replace any HVAC system components at your home before they become expensive problems. Contact us today for all your heating and cooling needs in Kingston, Ontario. 


Contact Details

Kingston Home Heating and Air

1154 Clyde Court,

Kingston, Ontario K7P 2E4

Bryant

Business Hours

Monday - Friday
08:00 AM - 04:00 PM
Saturday - Sunday
Closed

24-hour emergency service

24-hour service for heating only

Service Area

Kingston
Napanee
Seeleys Bay
Gananoque
Sydenham
Harrowsmith
Verona

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