Your furnace blower is what forces air through the furnace and then through your house via the heating ducts. The blower is a 3 part mechanism. These parts are:
- The blower housing or frame
- The blower wheel, also very often referred to as the squirrel cage
- The blower motor
Blowers can be direct drive or belt driven. Professionals often disagree over which style is better. This article will present some points in favor of direct drive furnace blower motor systems.
No Belt to Slip
In a direct drive system, there is no belt. The blower motor mounts inside the frame and blower wheel and the output shaft of the motor is connected directly to the blower wheel. This connection is secured by 1 or 2 set screws. If the wheel begins to slip, there is no belt to tighten, the set screws have come loose and just need to be tightened. A thread locking product such as Loc-Tite can make this less likely to happen. There are 2 main reasons a belt will begin slipping, these are stretching and loosening caused by motor or blower wheel movement. No matter what caused the belt to loosen, you’ll have to retighten it or the slipping will get worse until the belt finally overheats and fails. If this happens, you won’t have any central heating until you replace the belt.
No Belt to Break
When starting and stopping, the belt driving a belt driven blower wheel is placed under large amounts of stress. Over time, the belt will age, crack and finally break. Excessive slippage over time can also cause the belt to overheat and break, as previously mentioned. But if you’re using a direct drive furnace blower motor, there is no belt to get old and break.
Blower Motor Mounts Inside
With a belt driven blower wheel, the motor mounts outside the furnace housing frame and drives the blower wheel using a set of pulleys and a belt. In a direct drive furnace blower system, the motor mounts inside the blower wheel and frame. This significantly reduces the footprint, or spaced taken up by the furnace system. This decreased footprint increases usable storage area, or allows for a much smaller furnace enclosure or room.
Reduced Maintenance and Troubleshooting Time
In a direct drive furnace blower system there aren’t as many parts to fail as in a belt driven system, which means fewer parts to perform maintenance on. With a belt drive system, you’ll need to regularly condition and tighten the belt. If you’ve used a thread locker, you shouldn’t ever have to check a direct drive motor system.
Since there’s no belt to loosen and slip, you will save a little money by using a direct drive furnace blower system. Because the blower wheel is directly connected the motor, there is no lag due to belt slippage before the blower wheel comes up to full speed. There is also no torque loss due to the belt in a direct drive system.