2. Refrigerant system
2.1 Refrigerant system troubleshooting
Check the following items when troubleshooting the refrigerant system.
1) The thermostat setting or remocon temperature setting is not wrong?
2) Air filter is not cleaned?
3) Blower fan control switch is not at "low"?
4) Ventilation lever is not opened?
5) There is no obstacle in suction or discharge side of outdoor unit?
6) Dirty heat exchanger causes the heat exchanging efficiency to be down?
(Thorough cleaning)
7) Cooling/heating load is not increased?
8) Too many persons are in room? (Cooling)
9) The insulation of window gap is not wrong?
If there is no trouble from the above checks and also if there is no trouble on the electric appliances of
airconditioner body, it is assumed as refrigerant system failure.
a) Set aircon to High cool, run cooling for 15 min. or more, and measure the temperature difference of suc-
tion/discharge air in indoor unit. (Adjust the wind direction so that wind is discharged to the front direction in
the installed condition.)
b) Measure the voltage and current in running condition.
c) Measure the pressure of low pressure side in cooling condition.
(If the temperature is low, convert into the test switch.)
2.1.1 Temperature difference and current of suction/discharge air in evaporator
Temperature difference
of suction/discharge air
No temperature difference.
80% or less of rated current.
Temperature diff.: Under 8°C.
80% or less of rated current.
Temperature diff.: Under 8°C.
Rated current or over.
Temperature diff.: 8°C or over.
Gas leak (almost) Refrigerant
cycle closed
Gas leak, refrigerant cycle
closed, bad compressor
Excessive refrigerant charging
No refrigerant cycle trouble
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Running current
measurement
• Temperature difference of suction-discharge air
Normally, the temperature difference is based at 10°C. Actually, the judgemnt criteria is 8°C, because when the
room humidity is high, the temperature difference is small and when humidity is low, it becomes large.
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