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17. Troubleshooting Guide 
17.1  Refrigeration Cycle System 
In order to diagnose malfunctions, make sure that 
there are no electrical problems before inspecting the 
refrigeration cycle. 
Such problems include insufficient insulation, problem 
with the power source, malfunction of a compressor 
and a fan. 
The normal outlet air temperature and pressure of the 
refrigeration cycle depends on various conditions, the 
standard values for them are shown in the table on the 
right. 
 
 
Normal Pressure and Outlet Air Temperature (Standard) 
 
Gas pressure 
MPa (kg/cm
2
G) 
Outlet air 
temperature (°C) 
Cooling Mode  0.9 ~ 1.2 (9 ~ 12)  13 ~ 17 
Heating Mode  2.0 ~ 2.7 (20 ~ 27)  32 ~ 42 
*Condition:  • Indoor fan speed; High 
  • Outdoor temperature 35°C at cooling 
    mode and 7°C at heating mode. 
  • Compressor operates at rated frequency 
Difference in the intake
and outlet
air temperatures
More than 8°C
(15 minutes after an
operation is started.)
at cooling mode.
Above 14°C
(15 minutes after an
operation is started.)
at heating mode.
Less than 8°C at the cooling mode
Less than 14°C at the heating mode
Higher than specified
Lower than specified
Cooling Mode
High
Low
Low
Value of electric
current during operation
Gas side
pressure
Dusty condenser
preventing heat radiation
Excessive amount
of refrigerant
Inefficient compressor
•  Measuring gas side pressure
•  Measuring the air temperature
 difference
•  Measuring electric current
 during operation
Insufficient refrigerant
Clogged strainer or
capillary tube
Heating Mode
Low
Low
High
Inefficient compressor
Insufficient refrigerant
Clogged strainer,
capillary tube or
expansion valve
Normal