Detective Actuators:
Indoor unit Controller PCB
Heat exchanger (MID) thermistor
Detective details:
Heat exchanger (MID) thermistor is open or short is detected always.
Forecast of Cause :
1. Connector failure connection 2. Thermistor failure 3. Controller PCB failure
Check Point 1 : Check connection of Connector
Check if connector is loose or removed
Check erroneous connection
Check if thermistor cable is open
>>Reset Power when reinstalling due to removed connector or incorrect wiring.
OK
02-10
Trouble shooting 8
INDOOR UNIT Error Method:
Indicate or Display:
Indoor heat ex. thermistor error
Refer to error code table.
OK
Check Point 3 : Check voltage of Controller PCB (DC5.0V)
Make sure circuit diagram of each indoor unit and check terminal voltage at Thermistor (DC5.0V)
DC
Thermistor Characteristics (Rough value)
If Thermistor is either open or shorted, replace it and reset the power.
Check Point 2 : Remove connector and check Thermistor resistance value
Resistance Value ( )
Temperature (°C)
Resistance Value ( )
Temperature (°C)
1131.9 579.6 312.3 233.2 176.0 134.2 103.3 80.3 62.9
49.7 39.6 31.7 25.6 20.8 17.1 14.1 11.6 10.4
-30 -20 -10 -5 0 5 10 15 20
25 30 35 40 45 50 55 60 63
Resistance Value ( )
Temperature (°C)
Resistance Value ( )
Temperature (°C)
1013.1 531.5 292.9 221.1 168.6 129.8 100.9 79.1 62.5
49.8 40.0 32.4 26.3 21.6 17.8 14.8 12.3 11.1
-30 -20 -10 -5 0 5 10 15 20
25 30 35 40 45 50 55 60 63
If the voltage does not appear, replace Controller PCB.
H/E (MID) Thermistor
Room Temp. Thermistor
AU*G12/ 14/ 18LVLB
AR*G12/ 14/ 18LLTB
BLACK
BLACK
1
2
1
2
1 1
2 2
1 1
2 2
CN5
CN8
GRAY
GRAY
1
2
CN7
1
2
1
2
1
2
1
2
1
2
H/E (MID) Thermistor
Room Temp. Thermistor
BLACK
BLACK
CN5
CN8
GRAY
GRAY
CN7
BLACK
BLACK
AB*G18LVTB
AB/ AU type
AR type
AMP Air Conditioning
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