Why Is Your Furnace Blowing Cold Air in Rancho Cucamonga, CA?

Inland Empire Comfort
January 29, 2025
Furnace Repair in Rancho Cucamonga, CA

As a resident of Rancho Cucamonga, CA, you know that the winter months mean seeing the temperatures drop to the lower 40s. In those conditions, you literally need your furnace system firing on all cylinders.


So, it can be frustrating to find the furnace running but only blowing cold air. What are the common reasons why a furnace blows cold air? The top choice for furnace repair in Rancho Cucamonga covers all the details you need to know in this post.


The Thermostat Settings Are Out of Sorts

It sounds obvious, but many furnace problems are actually caused by issues with the thermostat. Remember, the thermostat tells your furnace when to run a heating cycle and when to enter the idling mode. Therefore, if your furnace blows cold air, you should check the settings to confirm that someone hasn’t changed them.


If you find out that the furnace isn’t running in the first place during your checks, you should consider changing the batteries. If it’s a new thermostat, then it’s probably not in sync with the furnace system, and you’ll need to talk to a furnace repair technician in Rancho Cucamonga about the replacement.


You Have a Clogged Air Filter in Rancho Cucamonga, CA

A dirty air filter is one of the top reasons why a furnace blows cold air while running. The filter traps airborne contaminants while the furnace runs. After it has accumulated too many contaminants, it will obstruct airflow to the furnace. This may trigger the furnace’s overheating protection mechanisms, causing the unit to end the heating cycle shortly after it begins.


Thus, you may only have cold air coming through your vents. Replacing the air filter is typically all you need to do to resolve the issue and get your furnace working properly again.


You Have Pilot Light Issues

If you have a furnace that was manufactured before 2010, then your system most likely has a pilot light that can go out for several reasons. The pilot light is a small blue flame that burns constantly once the furnace comes on. It helps ignite the burners at the beginning of a heating cycle. So, the furnace will not generate any heat if the pilot light is out.


If you notice that your pilot light is out, you can follow your owner’s manual to get it working again. If the light goes out too frequently or if you can’t relight it, you should contact a technician right away.


You Have a Malfunctioning Flame Sensor

Flame sensor problems are one of the reasons why a furnace blows cold air while running. The flame sensor is a thin, bent metal rod on the burner assembly in front of the pilot light. It’s there to confirm the presence of burning flames while the gas valve is open.


If it doesn’t detect any flames, it will shut down the furnace to protect your home from the effect of gas leaks. However, the sensor can still fail to detect flames if it’s coated in soot. Thus, it will shut down the furnace and cause cold air to come through your vents.


Gently cleaning the sensor with a soft cloth or fine-grit sandpaper can get it working optimally again.


You Have a Clogged Condensate Line

High-efficiency gas furnaces create condensate (which is essentially wastewater) while running. The water drains into the condensate line, a PVC pipe.


Clogs can form in the line if it’s clogged with dust, dirt, mold, or other debris. In this scenario, the condensate will start to accumulate around the furnace. The unit will shut down to protect itself, but the fan will keep on running—hence the cold air coming through your vents.

If your furnace is leaking water, cleaning the condensate line should get things working optimally again. However, removing debris from the line isn’t the easiest of tasks. Therefore, it’s best to leave it to experienced technicians.

Furnace Issues in Rancho Cucamonga, CA

Call Inland Empire Comfort for Your Furnace Issues in Rancho Cucamonga, CA

Have you experienced one of these reasons why a furnace blows cold air but haven’t had any luck with your DIY troubleshooting? Are you experiencing high winds and furnace problems? Get in touch with the knowledgeable, friendly experts at Inland Empire Comfort.


We can diagnose and repair problems affecting furnace systems of all makes and models. We don’t just fix the issue you think the furnace has; we’ll thoroughly check the system to ensure you don’t call us because your furnace is blowing cold air a few months later!

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