McQuay MWM Service Manual page 72

MCQUAY Service Guide Book
APJ1 –M5WMY10/15KR
Indoor LED Indication
The operation lamp (green) flashes when any of the following errors is detected.
1. When a protection device of the indoor or outdoor unit is activated or when the thermistor
malfunctions, disabling equipment operation.
2. When a signal transmission error occurs between the indoor and outdoor units.
Diagnosis Step
1. Hold down TIMER CANCEL button for 5 seconds, a "
display section.
2. Press TIMER CANCEL repeatedly until indoor buzzer produces a long beep. This indicates the error
code, refers to Error Codes table and is displayed on the temperature display section.
3. A short beep or two consecutive beeps indicate non-corresponding error codes.
4. To cancel the error code display, hold down TIMER CANCEL button for 5 seconds. Alternatively, the
code display will cancel itself if the button is not pressed for 1 minute.
Error Codes:
Error
Code
SYSTEM
Normal
00
Indoor-Outdoor combination fault
UA
Refrigerant Shortage
U0
Drop voltage or main circuit overvoltage
U2
Failure of transmission (between indoor
U4
and outdoor unit)
INDOOR UNIT
Indoor PCB defectiveness
A1
High pressure control or freeze-up
A5
protector
Fan motor fault
A6
Faulty heat exchanger temperature
C4
sensor
Faulty suction air temperature sensor
C9
OUTDOOR UNIT
Cooling-Heating switching error
EA
Circuit board fault
E1
OL started
E5
Faulty compressor start up
E6
Description
" indication flashes on the temperature
Error
Code
OUTDOOR UNIT
DC fan motor fault
E7
Over current input
E8
High temperature discharge pipe control
F3
High pressure control (in cooling)
F6
Sensor fault
H0
Operation fault due to faulty position
H6
detection sensor
DC current sensor fault
H8
Faulty suction air temperature sensor
H9
Faulty discharge pipe temperature
J3
sensor
Faulty heat exchanger temperature
J6
sensor
Electrical Part heat fault
L3
High temperature at Inverter circuit
L4
heat sink
Output over current
L5
Faulty Inverter circuit heat sink
P4
temperature sensor
71
Diagnosis
Timer Cancel
Description