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APPENDIX C — CONTROLS OPERATION
Fig. D — 85 Control Board
Board Function and Diagnostics
Unplug the blue connector from control board. Make appropriate
thermostat wiring connections and plug connector back to control
board. Refer to Tables E-F and Appendix Fig. D-F.
CN1 – 24V CUSTOMER INPUT (THERMOSTAT)
Use proper wire gauge and insulation type based on application
and local code requirements. For detailed 24V thermostat control
wiring diagrams, Refer to thermostat installation manuals.
CN2 – CHANGEOVER/RETURN AIR SENSOR
1. Power connector for 24V or Common-powered sensors
a. 24V Powered Sensors are applicable for Carrier-sup-
plied air sensor.
b. Common-powered Sensors are applicable for thermo-
stats by others.
2. Sensor/switch
a. 10k thermistor
b. Bimetal switch
CN3 – REMOTE SHUTDOWN INPUT
1. Provides dry contact for signal to BAS system – I/O
a. Dry Normally Open
b. Wet Normally Open
c. Discrete Coil
2. When contact activated
a. Motor OFF
b. Actuator OFF
c. Electric Heat OFF
d. Power to controller remains ON
3. BAS LED indication when BAS relay circuit activated.
Changeover/Return Air Sensor (CN2)
Pluggable T-Stat Connector (CN1)Remote Shutdown Input (CN3)
Two-Stage
Cooling (CN5)
Actuator & Aquastat (CN6)
Transformer (CN7) Line Service Voltage (CN8)
PSC Motor Connection (CN9)
ECM Connection (CN10)
ECM Fan Speed
Adjustment
LED Indication(s)
1
2
4
3
5
6
7 8
9
10
11
13
12
1 CN1 – 24V Customer Input (Thermostat)
2 CN2 – Changeover/Return Air Sensor
3 CN3 – Remote Shutdown Input
4 CN4 – Condensate Overflow Switch
5 CN5 –Two-Stage Cooling
6 CN6 – Actuator 7 Aquastat
7 CN7 – Transformer
8 CN8 – Line Service Voltage
9 CN9 – PSC Motor Connection
10 CN10 – ECM Connection
11 ECM Fan Speed Adjustment
12 Ground Connection
13 LED Diagnostics (for Multimeter Diagnostics)
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