Troubleshooting Guide

2.Field Maintenance
Possible causes of trouble
Power failure
Blown fuse or varistor
Loose connections Shorted or broken wires
Safety device opens
Faulty thermostat / room temperature sensor
Wrong setting place of temperature sensor
Faulty transformer
Shorted or open capacitor
Faulty magnetic contactor for compressor
Faulty magnetic contactor for fan
Low voltage Faulty stepping motor Shorted or grounded compressor
Shorted or
grounded fan motor
Unit will not start ☆ ☆ ☆ ☆ ☆ ☆
Compressor will not start but fans run ☆ ☆ ☆ ☆ ☆
Compressor and condenser fan will not start ☆ ☆ ☆
Evaporator (Indoor) fan will not start ☆ ☆ ☆ ☆
Condenser (Outdoor) fan will not start ☆ ☆ ☆ ☆ ☆
Unit runs, but shortly stops ☆ ☆
Compressor short-cycles due to overload ☆ ☆
High discharge pressure
Low discharge pressure
High suction pressure
Low suction pressure
Unit runs continuously but insufficient cooling
Too cool ☆ ☆
Compressor is noisy
Horizontal louver can not revolve ☆ ☆ ☆
Test method / remedy
Test voltage Inspect fuse type & size
Inspect connections - tighten Test circuits with tester
Test continuity of safety device
Test continuity of thermostat / sensor & wiring
Place the temperature sensor at the center of the air inlet
grille Check control circuit with tester
Check capacitor with tester
Test continuity of coil & contacts
Test continuity of coil & contacts
T
est voltage
Replace the stepping motor
Check resistance with multimeter
Check resistance with multimeter
Electrical Circuit
 Troubleshooting 17 