Mitsubishi Electric PUMY-P100VHM Technical & Service Manual page 39

Display
Meaning and detecting method
5101
Suction temperature thermistor (TH21)
abnormality
When controller detects short (high
temp.)/open (low temp.) in thermistor
during the operation, the operation stops
and the operation changes to protect
mode of restarting in 3 minutes. If the
thermistor does not recover in 3 minutes,
the operation stops abnormally. In this
time, <5101> is displayed. Then, if the
thermistor recover in 3 minutes, it operates
normally.
Short: Detected 90; or more
Open: Detected –40; or less
Discharge temperature thermistor (TH4)
abnormality
1
When controller detects short/open in
thermistor during the operation, the
outdoor unit stops once and restarts
operation in 3 minutes. When the detected
temperature is normal at just before of
restarting, the outdoor unit restarts.
2
When controller detects short/open in
thermistor at just before of restarting, the
unit stops abnormally. In this time, <5101>
is displayed.
3 For 10 minutes after starting compressor,
for defrosting or for 3 minutes after recover
of defrosting, above-mentioned short/open
are not detected.
Short: 216;or more (1k')
Open: 0; or less (700k')
Note) When outdoor temperature
thermistor (TH7) is 5; or less on cooling,
open detecting is not determined as
abnormality.
Causes
1 Connector (CN20) contact failure
2 Thermistor wiring disconnection or
half disconnection
3 Thermistor failure
4 Detecting circuit failure in the
indoor controller board
1 Connector (TH4) contact failure
2 Thermistor wiring disconnection or
half disconnection
3 Thermistor failure
4 Multi controller board input circuit
failure
39
Check points
1
Check whether the connector
(CN20) in the indoor controller board
is connected or not.
2
Check whether the thermistor wiring
is disconnected or not.
3 Check the resistance of thermistor;
0;···15k'
10;···9.6k'
20;···6.3k'
30;···4.3k'
40;···3.0k'
4
When there is no problem in above
mentioned 123,replace the indoor
controller board.
1
Check whether the connector (TH4)
in the multi controller board is
connected or not.
2
Check whether the thermistor wiring
is disconnected or not.
3
Check the resistance of thermistor;
When the resistance is not below
value, replace the thermistor.
0;··· about 700k'
10;··· about 410k'
20;··· about 250k'
30;··· about 160k'
40;··· about 104k'
1 3 4 5 6 7 8 2
on
Set the SW1 to
4
When the temperature in multi
controller board is not an actual
temperature, replace the multi
controller board.
1.3: Open
219.4: Short