Mitsubishi Electric CITY MULTI PURY-200M-B-BM. BSG Service Handbook page 22

[ V Troubleshooting ]
Temperature sensor failure (indoor unit)
Error Code
5101 Air inlet
5102 Liquid pipe
5103 Gas pipe
5104 (OA process-
ing unit)
Outdoor air
temperature
Error definition and error
detection method
If a short or an open is de-
tected during thermostat
ON, the outdoor unit
turns to anti-restart mode
for 3 minutes. When the
error is not restored after
3 minutes (if restored, the
outdoor unit runs normal-
ly), the outdoor unit
makes an error stop.
Short:
detectable at
90°C [194°F] or higher
Open :
detectable at
-40°C [-40°F] or lower
* Sensor error at gas-side
cannot be detected un-
der the following condi-
tions.
During heating oper-
ation
During cooling oper-
ation for 3 minutes
after the compressor
turns on.
-
Cause
(1) Thermistor failure
(2) Connector contact failure
(3) Disconnected wire or par-
tial disconnected ther-
mistor wire
(4) Unattached thermistor
sensor or contact failure
(5) Indoor board (detection cir-
cuit) failure
(1) The connection of the con-
nector CN29 is loose
(2) OA temperature sensor
failure
- 21 -
Check method and remedy
Check the thermistor resistor.
0°C [32°F]: 15 kΩ
10°C [50°F]: 9.7 kΩ
20°C [68°F] : 6.4 kΩ
30°C [86°F] : 4.3 kΩ
40°C [104°F] : 3.1 kΩ
Check the connector contact.
When no fault is found, the indoor
board is a failure.
Check the connector contact.
Replace the sensor.