Control Boards

The fan control board is the electronic "brain" that operates and regulates the fan in an HVAC blower motor assembly. Mounted inside the air handler or furnace, this circuit board contains components like transistors, capacitors, and relays as well as the microprocessor and programming that controls the fan. The board manages multiple fan operations including turning the blower on and off, adjusting fan speeds, monitoring safety switches, and activating special fan modes like delayed off.

Diagnostic LED lights on the control board can display error codes to help HVAC technicians troubleshoot fan malfunctions. Issues with the board can prevent the blower fan from turning on, cause the fan to run continuously, or lead to inconsistent fan speeds. Only replacing the board with the exact OEM part will properly restore fan function. While early fan control boards contained basic electromechanical components, modern versions utilize more sophisticated digital circuitry for added precision and capabilities. Upgraded control boards can provide greater efficiency, quieter performance, and new features. However, all replacement boards must be professionally installed and wired correctly to the blower motor to maintain proper, safe operation. As the brains directing fan activity, the fan control board is a crucial HVAC component that requires expertise to service and replace.