The controller verifies proper damper positioning by comparing the supply air temperature with the outdoor and indoor temperature. If the damper is completely open, the supply temperature should be the same as the outdoor temperature within a tolerance (configurable at FC2 under E Menu or at Pn in the Manufacturer Menu). If the damper is completely closed, the supply temperature should be the same as indoor temperature within a tolerance (configurable at FC3 under E menu or at Pn in the Manufacturer Menu).
Since the controller checks the damper by comparing temperatures, improper setup of the temperature sensors can cause erroneous alarms. Verify each damper’s physical movement through the step test. If the damper behaves correctly, refer to Sensor Setup Correction below. If the damper does not behave correctly, move to the Damper Fail section below.
Sensor Setup Correction
|Component to Check
|Incorrect supply air temperature setup
|SU1/ST3 must be in the supply air stream of unit 1. SU2/ST3’ must be in the supply air stream of unit 2.
|Correct sensor setup.
|Insufficient temperature tolerance
|FC2/3 under E menu
|Increase to 15-20°F.
|Improper outdoor temp sensor placement
|Outdoor temp sensor box must be placed in the shade. Indoor air leakage through the shelter wall into the outdoor sensor box
|Move the outdoor sensor box into shade. Seal the air leakage
|Component to Check
| Loose hardware
|Nuts on damper actuator. Ensure damper turns when the motor is turned manually,
|Tighten down loose hardware. Damper actuator can be accessed from the damper inspection panel on the side of the unit.
|Loose/incorrect damper actuator wiring
|Damper wiring: 24VDC between 12 and 13 for power, 10VDC between 10 and 12 for open position.
|Correct wiring. Refer to Damper Actuator Wiring below
|Incorrect damper actuator setting
|Check if damper actuator is moving in reverse direction
|Correct setting. The black round dial on the face of the damper actuator must be set to 0.
|Damper movement blocked/stuck
|Ensure Damper can rotate freely when disengaged from the actuator.
|Depress manual override on actuator and push on the damper. Clear any blockages.