A109_A: Suction Pressure Sensor Failure
Status
This is an active alarm, the air handler will operate with the EEV in a predetermined fixed position and should be repaired as soon as possible to prevent compressor damage and restore performance.
Description
This alarm is generated when the pressure transducer has failed or become disconnected. The system can no longer control superheat as suction pressure is part of that equation.
Cause
1. Pressure transducer has failed.
2. Control Board has failed.
3. Transducer wiring or connections are loose.
Solution
1. Check voltage to transducer to make sure roughly 5 vdc is provided via the red and black wires. Small needle meter leads can be placed in the back of the 3 pin plug at the control board. Check voltage from green to black which is the variable voltage. If no voltage is present, check harness connection at transducer on coil to ensure it is properly seated.
2. Check voltage to transducer to make sure roughly 5 vdc is provided via the red and black wires. If the board is powered but no voltage is provided, replace the control board.
3. Visually check connections at both ends of the harness to be sure they are properly seated.
