- Check whether all the breakers are flipped to ON
- Reset the controller by flipping the controller power breaker off and on
- Check the power supply to the fan
- Verify that 240V is going into the KA1 (wires 400 and 401)
- Common issue: The label on some of the controllers incorrectly states L, N (120V in U.S.) instead of L1, L2 (240V)
- Check the protection circuit is normal
- Verify that the signal between terminal 9 and 5 is NC
- Remove the right side panel to access the supply fan.
- Verify 240V is present from KA1 to the supply fan.
- Verify the 10V reference voltage from the supply fan
- If the reference voltage is significantly different from 10V contact HVAC support for replacement fan.