Part List - McQuay M5RT 90 BR Technical Manual

Error Message
12. Indoor fan overload
13. Return air sensor short / open
14. Outdoor air sensor short / open
15. Comp discharge sensor 1 / 2 short Faulty Sensor / Poor sensor connection
16. Comp discharge sensor 1 / 2 open Faulty Sensor / Poor sensor connection
17. Outdoor HEX sensor 1 / 2 short Faulty Sensor / Poor sensor connection
18. Outdoor HEX sensor 1 / 2 open Faulty Sensor / Poor sensor connection
19. Indoor HEX sensor 1 / 2 short
20. Indoor HEX sensor 1 / 2 open
There are two LEDs in economizer controller board, which are green LED and red LED. Green LED will blink
when economizer controller board is powered-up. Red LED will blink when error(s) occur. Refer the table
below for error codes and their meaning:-
Error
Fault
Code
F0 Fresh air actuator faulty/ malfunction
F1 Return air actuator faulty/ malfunction
F2 Communication error
F3 CO 2 sensor short
F4 CO 2 sensor open
F5 Fresh air RH sensor short
F6 Fresh air RH sensor open
F7 Return air RH sensor short
F8 Return air RH sensor open
F9 Activation of actuator protection
FA Multiple pins selection in Dip Switch 1, 2 or 3
Note:
When error(s) occur and the faults persist, please call your authorized local dealer/ serviceman for troubleshooting.
However, all the errors occur in economizer controller board will not affect the normal operation of rooftop unit.
Possible causes
Motor internal over current protection faulty
Winding resistance out of spec
Fan motor short body
Main PCB faulty
Faulty Sensor / Poor sensor connection
Faulty Sensor / Poor sensor connection
Faulty Sensor / Poor sensor connection
Faulty Sensor / Poor sensor connection
Note:
The error codes will be shown on the seven segment
display on the economizer controller board.
72
Action
Replace indoor fan motor.
Replace main PCB
Connect sensor correctly / replace sensor.
Connect sensor correctly / replace sensor.
Connect sensor correctly / replace sensor.
Connect sensor correctly / replace sensor.
Connect sensor correctly / replace sensor.
Connect sensor correctly / replace sensor.
Connect sensor correctly / replace sensor.
Connect sensor correctly / replace sensor.
Seven segment display