Och573 - Mitsubishi Electric MXZ-4C36NAHZ Service Manual

Check code
2503
Abnormal points and detection methods
<Drain sensor models>
Abnormal if drain sensor detects to be short/ open .
●Diagnosis of defectives
Make sure to turn the power OFF before connecting/disconnecting any connectors, or replacing boards
[Drain sensor models]
Check the drain sensor connector (CN31)
for disconnection or looseness.
Is it connected normally?
Is the resistance of thermistor normal?
<How to check the resistance>
Disconnect the connector for drain sensor from the indoor controller board to check the
resistance using a tester.
Temperature
0
10
20
25
30
40
60

OCH573

Drain senor abnormality
Diagnosis
Yes
Yes
Resistance
[32-F] 6.0 kΩ
[50-F] 3.9 kΩ
[68-F] 2.6 kΩ
[77-F] 2.2 kΩ
[86-F] 1.8 kΩ
[104-F] 1.3 kΩ
[140-F] 0.6 kΩ
<Drain sensor models>
Causes and check points
Contact failure of connector CN31
Characteristic defect of thermistor
Breakage or contact failure of drain sensor wiring.
Replace the indoor controller board.
Connect it properly.
Turn the power back ON, then check the
No
operation.
No
Replace the indoor controller board.
<Drain Sensor>
10
9
8
7
6
5
4
3
2
1
0
−4 32 68
−20 0 20
Temperature
61
Remedy
Replace the drain sensor.
104 140 176 (°F)
40 60 80 (°C)