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37 

š  Control start conditions 

o

  For 5 minutes, the compressor continuously operates and total current is low. 

o

  During Cooling or Soft Dry operation: 

Indoor intake temperature — indoor piping temperature is below 4°C. 

o

  During Heating operation: 

Indoor pipe temperature — indoor intake temperature is below 3°C. 

o

  Not during deice control. 

o

  Compressor ON with maximum frequency. 

š Control 

content 

o

  Compressor stops (and restart after 3 minutes) 

o

  If the conditions above happen 4 times within 60 minutes, the unit will stop operation (“F91” is indicated). 

 

š  This control detect gas leakage condition to prevent compressor damage. 

š  Control start condition 

o

  All connected indoor units capability supply ON. 

o

  Compressor ON with maximum frequency. 

o

  Not during annual cooling. 

o

  Compressor discharge temperature high. 

š Control 

content 

o

  Compressor OFF during this control (“F91” is memorized in EEPROM) 

o

  If the above conditions happen 2 times within 60 minutes, indoor units’ Timer LED will blinks (“F91” is 

indicated at all indoor units) 

 

š  This control detects 3-way valve close condition to prevent damage to refrigerant cycle. 

š Start 

conditions: 

o

  For all connected indoor units, if Indoor intake temperature — indoor piping temperature are between -2°C 

and 2°C continuously for 5 minutes after compressor ON at first cooling operation. 

o

  The first cooling operation is defined as cooling operation is ON for less than 8 minutes after new installation 

or after pump down. 

š Control 

content 

o

  During this control, compressor stop, indoor units’ Timer LED will blink. (“F91” is indicated at indoor units) 

š  Error reset can be done by power supply reset or reset by using remote control. 

 

š  This control protect by using high pressure switch during operation. 

š Start 

conditions 

o

  High pressure switch is activated (from normally close to open) when outdoor operation mode is cooling or 

heating during compressor running. 

š  Control 1 content 

o

  Compressor stop when high pressure switch is opened and restart after high pressure switch closed. If this 

condition happen 4 times within 30 minutes, “F94” is indicated. 

o

  After 30 minutes, counter is reset if this condition does not happen for 4 times. 

š  Control 1 stop conditions 

o

  Power supply reset 

o

  Reset by using remote control 

 
 
 
 
 
 
 
 
 
 

38 

 

 

š  Operate the pump down process according to the following procedure. 

o

  Confirm the valve on the liquid side and gas side are open. 

o

  Press PUMP DOWN button (SW1) on the Service PCB inside the outdoor unit for more than 5 seconds. 

Pump down (cooling) operation is performed for 15 minutes. 

o

  Set the liquid side 3 way valve to close position and wait until the pressure gauge indicates 0.01MPa 

(0.1kg/cm

2

G). 

o

  Immediate set the gas side valve to close position and then press the PUMP DOWN button (SW1) to stop the 

pump down operation. 

NOTE: Pump down operation will stop automatically after 15 minutes if PUMP DOWN switch (SW1) is not pressed 
again. Pump down operation is not started within 3 minutes after compressor is stopped. 

 

LED 2  3  4  5 Message 

Status 

 

 

 

 

Pump down operation in progress 

 

 

 

 

3 minutes before operation end 

 

 

 

 

2 minutes before operation end 

 

 

 

 

1 minute before operation end 

 

 

 

 

Pump down operation end 

: Flashing 

 
 
 
 

 

š  Test operation can be carried out using TEST OPERATION button (SW2) on the Service PCB inside the outdoor 

unit. 

š  For Cooling test, press the TEST OPERATION button (SW2) for 5 seconds or more but less than 10 seconds, 

LED1 and LED 2 will illuminate when shift into cooling test operation. 

š  For Heating test, press the TEST OPERATION button (SW2) for more than 10 seconds, LED 1 and LED 3 will 

illuminate when shift into heating test operation. 

š  Press the TEST OPERATION button (SW2) again to cancel test operation. 

 

39 

š  The unit capable to correct the wiring error automatically by following procedures. 

o

  Confirm the valve on the liquid side and gas side is open. 

o

  Press WIRING CHECK button (SW3) on the Service PCB inside the outdoor unit for more than 10 seconds 

to start wiring check operation. 

o

  Wiring check process will complete in approximately 20 - 25 minutes. However, wiring check operation will 

not start within 3 minutes after compressor is stopped. When outdoor air temperature is less than 5°C or unit 
has abnormality, wiring check will not start. (See NOTE 2) 

š  The LED 2 to LED 6 in Service PCB inside the outdoor unit indicate the possibility of the correction as shown in 

the table below: 

 

LED 2 3 4 5 6 Message 

Room A  B  C  D  E  

Status 

All flashing 

Automatic correction impossible

LED 2, 4, 6 and LED 3, 5 

alternatively flashing 

Wiring check in progress 

Flashing one after 

another 

Automatic correction completed 

Other than above 

Unit has abnormality (NOTE 4) 

š  If automatic correct is impossible, check the 

indoor unit wiring and piping manually. 

 

 

1.  For two rooms, LED 4,5 and 6 are not illuminated, for three rooms, LED 5 and 6 are not illuminated and for 

four rooms, LED 6 is not illuminated after wiring operation complete. 

2.  If the outdoor air temperature is less than 5°C or unit has abnormality, wiring operation will not start. 
3.  After wiring check operation is complete, LED indication will illuminated until normal operation starts. 
4.  Follow the product diagnosis procedure. (Check the diagnostic label at the cabinet side plate.) 
5.  When LED 1 only illuminate, indicates that outdoor unit is operating normally. 

š  Power Save Mode can be enabled by pushing POWER SAVE switch (SW4) to ON before power supply ON. 

š  When Power Save Mode is ON, the unit can be operate at lower running current where the breaker capacity not 

achieve the requirement. 

 

š  Mode priority function can be enabled by pushing MODE PRIORITY switch (SW5) to ON before power supply 

ON. 

š  When Mode Priority Function is ON, the mode priority is given to higher capacity indoor units. 

 

š  The unit capable to limit the operation mode to Cooling Mode only (Heating mode disabled) by cutting JP1 

(COOL ONLY) before power supply ON. 

š  This function prevent wrong operation during the unit installed in server room. 

š  This function could be disabled again by short the JP1 (COOL ONLY) before power supply ON. 

 
 
 
 
 
 
 
 
 
 

40 

š  The display screen of wireless remote control unit and the self-diagnosis LEDs (green) on the outdoor printed 

circuit board in the outdoor unit can be used to identify the location of the problem. 
Refer to the table below to identify and solve the cause of the problem, and then re-start the air conditioner 
system. 

š  If the problem is solved and operation returns to normal. 

LED 1 illuminates and others LED are off.