McQuay MWM Service Manual page 50

MCQUAY Service Guide Book
Ceiling Exposed D / E Series Model
Model
MCM 20/25/30/40/50D/DR
MCM 15/20/25/28E/ER
COOL DRY
(Green) (Orange) (Green)
Blink Heat, Cool, follow by Fan, Dry
ON /
Board
L208A
L208A
FAN HEAT
Error Code
(SLM3 /
Netware 3)
(Red)
ON or OFF
Handset
G17 / SLM3 / Netware 3 / SLM8
G17 / SLM3 / Netware 3 / SLM8
Operation / Faulty
Indication
- Cooling mode
- Dry mode
- Fan mode
- Heating mode
Auto mode in
-
cooling operation
Auto mode in
-
heating operation
Room air sensor
E1
contact loose / short
Indoor coil sensor
E2
contact open
Outdoor coil sensor
E3
contact open
Compressor
overload protection /
E4 Indoor coil sensor
short / Outdoor coil
sensor short
E5 Gas leak
Outdoor coil sensor
E7
exist (MS model)
Hardware error (tact
E8 switch pin short)
BLINKING
49
Diagnosis
Action
-
-
-
-
-
-
Check room sensor
connection / change room
sensor
Check indoor coil sensor
connection / change indoor
coil sensor
Check outdoor coil sensor
connection / change
outdoor coil sensor
If running ampere highly
increase, change the
compressor. If not, replace
the coil sensor
Check for leakage & repair
/ Top up refrigerant
Remove outdoor coil
sensor
Replace the tact switch
control board