4 Reasons The Furnace Blower Might Not Shut Off

The blower in your furnace should run intermittently. If it runs all the time, there's a problem somewhere. You may want to call in a furnace repair technician as soon as you notice this problem so your home doesn't lose heat if the blower starts putting out cool air. Here are four possible reasons for a furnace blower that keeps running.

1. The Thermostat Setting Is Too High

If the setting on your thermostat accidentally got switched to a setting or temperature that's so high that your furnace can't reach it, then your blower may just keep running continuously. You'll probably also notice your home getting warmer. This could eventually trigger a limit switch that shuts your furnace down so it doesn't work at all.

The first thing a furnace repair technician may do is check the error codes on the furnace to narrow down the problem. If the problem is a wrong setting on the thermostat, dialing in the right temperature might fix the furnace.

2. A Thermostat Wire Is Broken

A similar problem happens when the thermostat wire is damaged. In this case, the blower might continue to run even if the thermostat is turned off. To repair this situation, the furnace repair technician has to determine if the bad wire is the only point of damage. If so, the wire can be repaired or replaced and the connection fixed so the thermostat can control the furnace again.

3. The Blower Motor Is Malfunctioning

The blower motor receives a signal to turn on and turn off. If the signal to turn off is not received due to a malfunction of the motor, then the motor keeps working and spinning the blower. When this problem happens, the furnace repair technician may need to replace the blower motor.

4. The Fan Limit Control Is Bad

The fan limit control is what turns the blower on and off based on temperature limits. If the settings were changed somehow, the furnace repair technician can restore them so the control works properly. However, it's also possible for the fan limit control to go bad and stop working. When that happens, the technician can replace it with a new one.

A furnace blower can malfunction in different ways. It may not turn off or it may not turn on. Sometimes it turns on, but it doesn't put out much air. A furnace repair technician can sometimes narrow down the problem by noticing the way the blower functions and reading the codes on the furnace.

The technician may also need to use a multimeter to test for bad parts. After troubleshooting the issue, the technician can replace bad parts or make repairs so the blower turns on and off as it should so your home stays warm and your power bill stays low.