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1. WORKING INSPECTION (When cooling)
SYMPTOM
(1) Indoor unit evaporator is
coated with frost.
a. Frost near inlet
b. Frost all over
(2) Compressor operates, but it
does not cool.
(3) Water does not come out of
drain hose.
(4) Return pipe (low pressure) of
compressor is not cold.
(5) Outlet pipe (high pressure) of
compressor is not hot.
(6) Compressor operates, but
does not cool.
a. Indoor unit evaporator is
cold.
b. Outdoor unit condenser is
hot, but it does not cool.
(7) Indoor unit air outlet
temperature is low, but it does
not cool.
2. SYMPTOMS AND CHECK ITEMS
SYMPTOM
No operation
Erroneous operation
(Runaway)
Display does not light
correctly.
Room temperature cannot
be controlled.
Room fan does not run and
wind speed cannot be
switched.
Indication panel abnormal
TROUBLESHOOTING GUIDE
POSSIBLE CAUSES
Gas leakage
Clogged filter
Low ambient temperature
(less than 20°C)
Stained condenser
When the compressor operates
normally, the gas leaks.
Gas leakage
Gas leakage
Overload operation
Stained condenser
Clogged filter
The cooled air is shorted.
Overload operation
CAUSES
Power supply circuit faulty
Microcomputer reset
circuit faulty
Remote control faulty
External wiring receiving
section faulty
Microcomputer runaway
Display unit faulty
LED driver faulty
Room thermistor faulty
Pipe temperature thermistor
faulty
A/D converter input section
faulty
Compressor relay circuit faulty
Wind speed relay faulty
Thermistor shorted or open
CHECK ITEM
CHECK 1
CHECK 2
CHECK 3
CHECK 4
CHECK 5
CHECK 8
CHECK 6
CHECK 7
CHECK 9
– 15 –
REMEDY
Check leaking part, and charge
gas.
Clean filter.
Check ambient temperature.
Clean.
Charge gas and replace parts.
Charge gas.
Replace parts.
Charge gas.
Eliminate overload.
Clean.
Clean.
Isolate problem and correct.
Eliminate overload.
CHECK POINTS
Power supply circuit
Microcomputer input
signal
Remote control
troubleshooting
Reset circuit
Display unit
Microcomputer output
signal
Driver output signal
Thermistor resistance
value
Microcomputer input
signal
Relay output
Microcomputer output
signal
Driver output signal
Thermistor resistance
value
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