Mark HCNI 533, Техническое руководство

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52
1. Field Maintenance Electrical Circuit
Possible causes of trouble
Power failure Blown fuse or varistor Loose connecons Shorted or broken wires Safety device opens Faulty thermostat / room temperature sensor Wrong seng place of temperature sensor Faulty transformer Shorted or open capacitor Faulty magnec contactor for compressor Faulty magnec 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
(outdoor) 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 sucon pressure
Low sucon pressure
Unit runs connuously but insuf-
ficient cooling
Too cool
Compressor is noisy
Horizontal louver can not
revolve
Test method / remedy
Test voltage Inspect fuse type & size Inspect connecons - tighten Test circuits with tester Test connuity of safety device Test connuity of thermostat / sensor & wiring Place the temperature sensor at the central of the air inlet grille Check control circuit with tester Check capacitor with tester Test connuity of coil & contacts Test connuity of coil & contacts Test voltage Replace the stepping motor Check resistance with mulmeter Check resistance with mulmeter