The blower fan is an essential portion of furnaces. Problems with the blower fan and the portions of the heating system that it needs to work properly may cause homeowners to experience issues such as noisy furnace operation or no heat. Furnace services are usually required for blower fan issues because there are other issues that can mimic fan system issues. Any furnace that exhibits problems and has not had routine furnace maintenance services needs to be inspected by an HVAC contractor even if homeowners think that they can fix the issue. Assuming that a simple fix is doable without a professional means that there are unknown issues that could render mechanical failure. The following points represent a few things that are blower-fan-related.
The blower wheels in furnaces can get off-balance or broken. Balance issues can be corrected through readjustments. This can be done as a furnace service during routine appointments. Technicians perform tests to detect wheel issues and fix or replace them if needed. Trapped debris is a common cause of wheels becoming unbalanced. You can inevitably expect to hear strange noises when there are wheel issues. Broken wheels mimic the sound of scraping metal against metal.
If the bearings are the blower issue, the furnace operation will likely be noisy. The repair will likely involve determining if overheating has contributed to wearing down the bearings. Damaged capacitors can contribute to overheating and worn capacitors. This is an issue that presents itself with noticeable squealing sounds during furnace operation. A blower fan belt issue may also make this sound.
Sometimes motor issues are related to neglecting required furnace services or aged furnaces. The motors may also overheat and shut down until they cool and are safe to resume operation. Furnace repairs can fix motor issues, but issues that have not been addressed in a timely manner could make it more sensible to get a furnace replacement if there are other heating system issues.
Blower Control Issues
It is possible to have a working blower that has been inactivated due to a safety control feature. This could be the case if you have a newer model furnace. The feature is designed to prevent furnace operation if an issue exists. Sometimes the issue can be resolved by flipping the safety switch back into place. If the safety switch stops furnace operation again, you need to let a professional inspect, diagnose, and perform the furnace repair.