Condition
Air proving switch failed to open
The air proving switch has failed closed, check switch is operating properly. The air proving switch is “Closed” when it should be “Open”. The air proving switch is checked for proper function before the blower is started and the start sequence is allowed to continue. If the air switch is closed before the blower is started (when there is no air Àow) first a soft lockout is initiated and then a manual reset hard lockout results.
Possible Cause
- The air proving switch is jumpered.
- The air proving switch is defective.
- The blower is running before the start sequence starts the blower. This can be caused by a loss of communication between the blower and Control. The blower goes to high speed when there is no communication between the Control and the blower. Possible cause of loss of communication is a defective wiring harness, blower or Control.
