Mitsubishi Electric PEAD Series Service Manual page 38

TROUBLESHOOTING
10-6. TROUBLE CRITERION OF MAIN PARTS
PEAD-A12AA7
PEAD-A18AA7
PEAD-A24AA7
PEAD-A30AA7
PEAD-A36AA7
PEAD-A42AA7
Part name
Room temperature
thermistor
(TH1)
Pipe temperature
thermistor/liquid
(TH2)
Condenser/evaporator
temperature thermistor
(TH5)
Wiring diagram
10-7. Thermistor
<Thermistor Characteristic graph>
Room temperature thermistor (TH1)
Thermistor for
Pipe temperature thermistor (TH2)
lower temperature
Condenser/evaporator temperature
thermistor (TH5)
Thermistor R
0
1
Rt=15exp { 3480(
273+t
HWE16080
Measure the resistance with a tester.
Normal
Vm (Power supply for motor)
Vcc (Power supply for control)
Regulator
Vsp (Speed command voltage)
PG (Pulse output for rotation)
GND
1
–
) }
273
Check method and criterion
Abnormal
Opened or short-circuited
Motor
Board with build-in motor
Hall IC
Power
device
Current detecting resistor
< Thermistor for lower temperature >
50
40
30
20
10
0
-20 -10 0
-4 14 32 50 68 86 104 122
38
Motor winding
Pre
driver
(˚C)
10 20 30 40 50
˚F
Temperature