2 Possible Reasons Why Your Furnace's Blower Motor Is Overheating

Lately, you may have noticed that your furnace seems to be switching off before your home warms up to the temperature you have set on the thermostat. If this is happening, the furnace may be short cycling because the blower motor is overheating and activating the safety switch to turn it off. There are a couple of possible reasons why your furnace's blower motor keeps overheating and trigger the emergency off switch.

1.  Dust Buildup Is Causing a Block in the Airflow

One possible reason why the furnace's blower motor is overheating is that dust buildup is causing a block in the airflow through the system. When the system does not allow for free movement of air through it, the heat that is meant to warm your home becomes trapped inside of the unit.

As the internal temperature of the unit increases, so does the temperature of the blower motor. Once an excessive level is heat is reached, the safety switch will trigger and shut down the motor to keep it from becoming severely overheated.

While ensuring that the furnace's filter is changed monthly and the vents are clear from dust, there may also be dust accumulation within the motor itself. If this is the case, you will need a professional to clean it out.

2.  Poor Lubrication Is Causing Excess Bearing Friction

Another possible reason for the overheating and short cycling of the furnace's blower motor is that the bearings within the motor are not fully lubricated. If the lubricant on the bearings is low or deteriorated, the bearings will create a lot of friction while the motor is running.

Because of the excess friction, the heat within the motor will rise. Once the safety limit is reached, the switch will shut down the cycle to keep the bearings and the motor from heating up.

While replacing the lubricant will usually solve the issue, the bearings may also need replacing. Their replacement depends on how much wear they suffered while poorly lubricated. The contractor doing the work will be able to determine whether or not this is necessary.

No matter what is causing your furnace's blower motor to overheat and short cycle, if you do not have a professional fix the issue, the motor may eventually seize up, requiring that you have it replaced. As soon as possible, contact an HVAC contractor who offers furnace repair services to have them inspect the system to pinpoint the problem and take the necessary action to fix whatever is causing the issue.

If you have additional questions about furnace repair, contact a local HVAC technician.