My Furnace Is Blowing Cold Air, What Is the Reason?

It’s a fear of any homeowner: the furnace is blowing cold air for no apparent reason. There are a number of reasons for a furnace to stop doing its job. Calling a Loveland furnace repair expert can help you find the source of the problem and bring back the warm air into your house. Here are the most common possible reasons for a furnace to blow cold air.

The Thermostat Settings Keep the Fan Blowing

A simple setting on the thermostat can keep air constantly blowing, no matter if it is hot or cold. If the fan setting is set to “on,” the fan will run constantly. The simple fix is to turn the fan setting to “auto,” which means the furnace will only blow warm air. The thermostat could also be set to the wrong temperature. The thermostat is a good place to start whenever there is a furnace issue. With any luck, it will be an easy fix that doesn’t require repairing or replacing furnace parts.

The Furnace is Overheated

When a furnace gets too hot, the limit switch automatically turns the burners off. In order to cool the furnace down to a safe temperature, the blower keeps blowing, which is what may keep cold air blowing through your system. Most furnaces overheat because the air filter is dirty and needs to be replaced. A dirty air filter blocks the airflow, which causes the furnace to work harder and longer to heat the house. As the furnace works longer, the temperature increases until it overheats. The easiest way to fix this problem is to replace the air filter and see if the furnace starts blowing warm air. Ignoring this furnace problem will only make things worse can lead to much more expensive repairs if the furnace keeps overheating.

The Flame Sensor Needs to be Cleaned

Modern furnaces, or those installed in the last 10 to 15 years, use an ignitor and flame sensor to turn on instead of a pilot light. The ignitor starts the fuel running and then turns on the flame sensor to start heating the home. However, if the flame sensor is dirty, the furnace will turn on but will then start blowing cold air. The flame sensor is a sensitive piece that either needs to be cleaned or replaced. It naturally gets dirty with normal furnace use. If you’re familiar with the piece, you can try cleaning it yourself. Otherwise, the best option is to call an HVAC professional to clean the flame starter. They will be able to tell you if the part needs to be replaced or if it can simply be cleaned to fix the problem.

The Pilot Light is Out

Older furnaces use pilot lights to continually send fuel to the starter and turn the furnace on. If the pilot light goes out, the furnace won’t heat and can blow cold air instead. The pilot light can turn off if it gets dirty or if there is a gust of air. Check the status of the pilot light and re-light it if it’s out.

There’s a Hole in the Ductwork

Another possibility is that there’s a hole or leak in the ductwork that is causing cold air to get in and blow throughout the house. This isn’t as common of a reason, but it can be worth investigating if the other ideas haven’t led to a solution. Have an HVAC technician look through your ductwork to find any holes or areas where cold air could be leaking in.

There are a number of reasons why a furnace could be blowing cold air. Some reasons have relatively easy solutions, and others are more complicated. If you’re not sure why the furnace is blowing cold air or if you need someone to make a complicated repair, call an HVAC professional. These technicians can work through the entire system to find the source of the problem, fix it, and help make sure the furnace stays in good working order. With proper maintenance and the right repairs, your furnace can be back to blowing hot air in no time.

Ready to bring in the experts? Call leading Northern Colorado HVAC contractors, American Air, at 970-686-6086.