Trouble Criterion Of Main Parts - Mitsubishi Electric MSC-A07WV Service Manual

Indication
Abnormal point
LED 1 LED 2
(Red) (Yellow)
Once Lighting Current protection
Twice Lighting High pressure protection When indoor pipe temperature exceeds 55˚C during heating.
Twice Lighting Defrosting in cooling
Discharge temperature
3 times Lighting
protection
Low discharge
4 times Lighting
temperature protection
5 times Lighting High pressure protection When high pressure protect thermistor detects 58: or more.
6 times Lighting Overload protection
Indication
Abnormal point
LED 1 LED 2
(Red) (Yellow)
Lighting 5 times Defrost thermistor
Lighting 6 times Power factor detection
Lighting 8 times Active filter module protection When active filter module self-protection has been performed.
Lighting 9 times Service mode
13-4.

Trouble criterion of main parts

MSC-A07WV -
E1
MSC-A09WV -
E1
MSC-A12WV -
E1
Part name
Room Measure the resistance with a tester.
temperature
(Part temperature 10°C ~ 30°C)
thermistor (RT11)
Indoor coil
thermistor (RT12)
Measure the resistance between the terminals with a tester.
(Coil wiring temperature10°C ~ 30°C)
Indoor fan
motor (MF)
INNER FUSE
136i3°C Measure the voltage Power ON.
CUT OFF
Measure the resistance between the terminals with a tester.
(Part temperature10°C ~ 30°C)
Vane motor
(MV)
Symptom: Outdoor unit operates (The compressor operates at reduced frequency)
When the outdoor unit input current exceeds 13A.
When indoor pipe temperature falls to 6˚C or below during cooling.
When the discharge temperature exceeds 104˚C.
When the state with low discharge temperature of which 37˚C or below
in COOL and 35˚C or below in HEAT for 20 minutes.
When the compressor load exceeds the specified value.
Symptom: Outdoor unit operates.
When a short or open circuit occurs in the defrost thermistor during
heating.
When the compressor power factor cannot be detected.
When operating unit with compressor relay connector disconnected.
Check method and criterion
Normal
MSC-A07/A09/A12WV
8kΩ ~ 20kΩ
Color of
lead wire
MSC-A07/A09WV
WHT-BLK 396 ~ 430Ω
320 ~ 348Ω
BLK-RED
Normal
Color of
lead wire
MSC-A07/A09/A12WV
BRN-YLW
4.5 ~ 5.5V
(When fan revolved one time)
YLW-GRY
0V 5V 0V
(Approx.)
Normal
MSC-A07/A09/A12WV
240 ~ 260Ω
Detecting method
Detecting method
Abnormal
Open or
short-circuit
Normal
MSC-A12WV
303 ~ 329Ω
287 ~ 311Ω
Abnormal
Remain 0V or 5V
Abnormal
Open or
short-circuit
109
Check points
These symptoms do not mean any
abnormality of the product, but check
the following points.
• Air filter clogging.
• Amount of gas.
• Short cycle of indoor/outdoor air flow.
Check points
• Check the characteristic of the defrost
temperature thermistor.
• Check the connector. (CN662)
• Check the compressor wiring.
Abnormal
Open or
short-circuit
RED
YLW
BRN
Figure
WHT
RED
BLK
FUSE
YLW
GRY
BRN
ROTOR
ORN GRN