Why is my furnace blowing cold air?
It’s winter, and you’re chilled. Wisconsin winters are no fun without the heat. The last thing you want is for your furnace to be blowing cold air.
Here are some possibilities as to why your furnace might be blowing cold air that you can check yourself:
Your Thermostat is set to ON: This comes into play when your furnace is blowing cold air only some of the time. You want to check your thermostat and see what setting it is on. If it is set to ON, your furnace is going to run all the time, regardless of whether it is heating the air or not.
How to fix it? Set the fan to AUTO instead. This will have it blow air only when it is being heated.
Your Air Filter is Dirty: If your furnace’s air flow is dirty, it can restrict air flow. When this happens, your furnace can overheat, which then triggers safety measures that turns off the burners in your furnace.
Replace your air filter, and see if the problem is fixed. If it is, then it was simply an issue of your air filter being dirty.
Your Pilot Light is Out: If the pilot light on your furnace is out, your furnace will only blow cold air.
The first thing you should try is to simply relight the pilot light; if it stays lit, you likely will be good to go. Sometimes, this won’t work. If that is the case, you need to make sure that gas is actually flowing into your furnace. Check to see if the gas valve switch is set to the ON position. The last typical issue with a pilot light is that it will light, but it won’t stay lit. When this happens, there is an issue with what is called the thermocouple. It is the copper rod that the flame hits. If this is the case, it needs to be adjusted or replaced typically. This solution is easier done by a professional, unless you know what you are doing.
There are other issues that are possible, but these are three common ones that you would be able to fix yourself. Need help?