Troubleshooting; Driver Display Panel Alarm Message Definition - Carrier 68G5-105 Series Operation & Service Manual

Do not under any circumstances attempt to service the microprocessor. Should a problem develop
with the microprocessor, replace it.
To access LED display on the microprocessor, remove cover
from main control box located in rear of electrical compartment.
ERROR STATUS OF
CODE LED DISPLAY
0 1 sec on - 1 sec off
1 1 flash - 5 sec pause
2 2 flashes - 5 sec pause
3 3 flashes - 5 sec pause
4 4 flashes - 5 sec pause
5 5 flashes - 5 sec pause
6 6 flashes - 5 sec pause
ERROR
MESSAGE
CODE
Er4 Communications Failure
Er5 Data Memory
Er6 Program Memory
ALARM
TITLE
NO.
A11 Main Left
Probe Failure
A12 Main Right
Probe
Failure
SECTION 3

TROUBLESHOOTING

Table 3-1. Microprocessor Error Message Definition
Not Applicable as system is operating normally.
Record error code number, tag and replace the microprocessor.
Record error code number, tag and replace the microprocessor.
Record error code number, tag and replace the microprocessor.
Record error code number, tag and replace the microprocessor.
Record error code number, tag and replace the microprocessor.
Record error code number, tag and replace the microprocessor.
Table 3-2. Display Error Message Definition
If the display does not receive data from the microprocessor.
If memory on the display is not verified on power up.
If program memory on the display is not verified on power up by a checksum.
Table 3-3. Driver Display Panel Alarm Message Definition
CAUSE
Sensor is unplugged,
wiring defective or
main left evaporator
return air temperature
sensor failure.
Sensor is unplugged,
wiring defective or
main right evaporator
return air temperature
sensor failure.
CAUTION
NOTE
REMEDY
MESSAGE DEFINITION
REMEDY
Ensure sensor is
plugged in. Check
sensor resistance or
wiring. Replace sen-
sor or repair wiring.
(Refer to section 4.13
and Table 4-3.)
Ensure sensor is
plugged in. Check
sensor resistance or
wiring. Replace sen-
sor or repair wiring.
(Refer to section 4.13
and Table 4-3.)
3-1
MICROPROCESSOR RESPONSE
Switches to the right probe. If both
probes are bad, the microprocessor
will run in the full reheat and evapo-
rator fans will operate on low speed.
The compressor will operate on six
cylinders if pressures permit.
Switches to the left probe. If both
probes are bad, the microprocessor
will run in the full reheat and evapo-
rator fans will operate on low speed.
The compressor will operate on six
cylinders if pressures permit.
T-312