68-0173—3 40
TROUBLESHOOTING

See Fig. 41 for troubleshooting procedures.

Fig. 41. Troubleshooting procedures.

1. PRESS THE CHECK KEY.
PC8900 DISPLAY SHOWS:
WRONG DISCHARGE AIR SENSOR
IS INSTALLED. • CHECK THAT C7100 DISCHARGE AIR SENSOR IS BEING USED.
• CHECK THAT C7100 DISCHARGE AIR SENSOR IS BEING USED.
WRONG DISCHARGE AIR SENSOR IS
INSTALLED.
• CHECK THAT C7100 AVERAGING DISCHARGE AIR SENSOR IS
BEING USED.
WRONG DISCHARGE AIR SENSOR IS
INSTALLED.
• RECONFIGURE PC8900.
PC8900 CONFIGURED FOR DISCHARGE
AIR TEMPERATURE SENSOR, BUT NOT
INSTALLED.
POSSIBLE CAUSE ACTION
IF THE CHECK LED IS LIT, USE THE FOLLOWING TROUBLESHOOTING INFORMATION.
M6193B
• REPLACE PC8900.
PC8900 HUMIDITY SENSOR IS
INOPERATIVE.
PC8900 TEMPERATURE SENSOR HAS
FAILED.
• REPLACE PC8900.
• RECONFIGURE PC8900 FOR REMOTE SENSOR USE.
• CHECK CONNECTIONS BETWEEN C7100 AND W8900.
W8900 CANNOT READ DISCHARGE
AIR TEMPERATURE.
• CHECK THAT C7100 DISCHARGE AIR SENSOR IS BEING USED.
WRONG DISCHARGE AIR SENSOR IS
INSTALLED.
• RECONFIGURE PC8900.
PC8900 CONFIGURED FOR DISCHARGE
AIR TEMPERATURE SENSOR, BUT NOT
INSTALLED.
• CHECK CONNECTIONS BETWEEN C7100 AND W8900.
W8900 CANNOT READ DISCHARGE
AIR TEMPERATURE.
• RECONFIGURE PC8900 FOR LOCAL SENSOR ONLY.
PC8900 CONFIGURED FOR OUTDOOR
TEMPERATURE SENSOR, BUT NOT
INSTALLED.
• CHECK THAT C7089 OUTDOOR TEMPERATURE SENSOR IS
BEING USED.
WRONG OUTDOOR TEMPERATURE
SENSOR IS INSTALLED.
• CHECK CONNECTIONS BETWEEN C7089 AND W8900.
W8900 CANNOT READ OUTDOOR AIR
TEMPERATURE.
1. CLEAN AIR CLEANER CELLS OR REPLACE AIR FILTER.
2. PRESS CANCEL KEY WHILE VIEWING FILT CHG MESSAGE.
FAN RUN TIME HAS EXCEEDED
720 HOURS.
HEAT PUMP COMPRESSOR FAILURE
RELAY HAS ENERGIZED W8900 L
TERMINAL.
• CHECK HEAT PUMP. REFER TO MANUFACTURER
SPECIFICATIONS TO TROUBLESHOOT EQUIPMENT.
• CHECK CONNECTIONS BETWEEN C7100 AND W8900.
• REFER TO MANUFACTURER SPECIFICATIONS TO
TROUBLESHOOT EQUIPMENT.
DISCHARGE AIR SENSOR IS PRESENT
AND INDICATES A HEAT SYSTEM
FAILURE WHILE IN HEATING MODE.
COMMUNICATIONS WITH THE HOME
SYSTEM AND W8900 CANNOT
BE ESTABLISHED.
• CHECK CONNECTIONS BETWEEN HOME SYSTEM AND
COMMUNICATION MODULE.
• CHECK COMMUNICATIONS BUS.
• RECONFIGURE PC8900
CONNECTION BETWEEN PC8900 AND
W8900 CANNOT BE ESTABLISHED.
• RECONFIGURE PC8900.
• CHECK CONNECTIONS BETWEEN C7100 AND W8900.
• REFER TO MANUFACTURER SPECIFICATIONS TO
TROUBLESHOOT EQUIPMENT.
DISCHARGE AIR SENSOR IS PRESENT
AND INDICATES A COOL SYSTEM
FAILURE WHILE IN COOLING MODE.

a

IF THE COMM CHK LIGHT IS CAUSED BY HEAVY COMMUNICATION FROM THE CM8900, IT DISAPPEARS IN 5 SECONDS. NO ACTION IS NEEDED.

a