EXCB Motor Failure Alarm — Intake or Exhaust Motor Problem

What does EXCB Motor Failure Alarm mean?

This alarm is triggered if the outside air or exhaust motor detects a problem, such as phase loss or thermal overload. The system will close its alarm contact, visible as 24vac at EXCB J8-3.

• Phase loss in motor power
• Locked rotor condition
• Motor thermal overload
• Communication error with the motor
• Incorrect signal to the motor
• Fan failure

Click steps to track your progress.

1. 1

   Check the motor's power supply for phase issues.

2. 2

   Ensure the motor is not mechanically blocked (locked rotor).

3. 3

   Allow the motor to cool down if it has thermally overloaded.

4. 4

   Verify motor wiring and communication signals.

5. 5

   Reset the alarm after the condition is cleared.