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• This control detect outdoor pipe temperature and perform the compressor frequency restriction during cooling operation.

• This control detect indoor pipe temperature and perform the compressor frequency restriction during heating operation.

• This control detect outdoor ambient temperature and perform the fan speed adjustment during heating operation.

• This control is to prevent low pressure drops too low during extremely low outdoor ambient temperature to improve the

compressor reliability.

• During heating operation, when outdoor ambient temperature is in Zone 1, this control will be activated. Compressor frequency

restriction will be based on outdoor piping temperature.

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• When outdoor pipe temperature and outdoor air temperature is low, deice operation starts where indoor fan motor and outdoor

fan motor stop, indoor unit horizontal vane close and operation LED blink with compressor ON.

• The compressor will not restart within three minutes after compressor is stopped.
• This control is not applicable if the power supply reset or after deice condition.

• Once the compressor starts operation, it will not stop its operation for 30 seconds in order to cycle back compressor oil.
• However, it can be stopped using remote control or Auto OFF/ON button at indoor unit.

• By referring to table below, during normal (default) operation, the running current refer to Hi values and during Power Save

Mode, the running current refer to Lo values.

• When the outdoor unit total running current (AC) exceeds X value, compressor frequency will decrease.
• If the running current does not exceed X value for 5 seconds, compressor frequency will increase.
• However, if total outdoor unit running current exceeds Y value, compressor will be stopped immediately for 3 minutes.

• Overheating Prevention Control

- If IPM temperature rises to 80

°C, outdoor fan speed will be increased.

- When the IPM temperature rises to 95

°C, compressor operation will stop immediately.

- Compressor operation restarts when temperature decreases to 90

°C.

- If IPM temperature detected less than -30

°C, IPM is judged as open circuit (“F96” is indicated).

• DC peak current control

- When IPM DC current exceeds set value of 30.0 ± 3.0 A, the compressor will stop.
- If the DC peak current detected within 30 seconds after operation starts, compressor will restart after 1 minute.
- If the DC peak current detected 30 seconds or more after operation starts, compressor will restart after 2 minute.
- Within 30 seconds after compressor restarts, if the DC peak current is exceeded set value continuously for 7 times, all indoor

and outdoor relays will be cut off (“F99” is indicated).

• Error reset can be done by power supply reset.

• Control start conditions

- For 5 minutes, the compressor continuously operates and total current is low.
- During Cooling or Soft Dry operation:

Indoor intake temperature — indoor piping temperature is below 4

°C.

- During Heating operation:

Indoor pipe temperature — indoor intake temperature is below 3

°C.

- Not during deice control.
- Compressor ON with maximum frequency.

• Control content

- Compressor stops (and restart after 3 minutes)
- If the conditions above happen 4 times within 60 minutes, the unit will stop operation (“F91” is indicated).

Operation Mode

CU-4E23JBE

CU-3E18JBE

X (A)

Y (A)

X (A)

Y (A)

Cooling/Soft Dry (A)

Hi

14.0

17.5

14.0

17.5

Lo

9.8

17.5

9.8

17.5

Cooling/Soft Dry (B)

Hi

14.0

17.5

14.0

17.5

Lo

9.8

17.5

9.8

17.5

Heating

Hi

14.0

17.5

14.0

17.5

Lo

9.8

17.5

9.8

17.5

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• This control detect gas leakage condition to prevent compressor damage.
• Control start condition

- All connected indoor units capability supply ON.
- Compressor ON with maximum frequency.
- Not during annual cooling.
- Compressor discharge temperature high.

• Control content

- Compressor OFF during this control (“F91” is memorized in EEPROM)
- If the above conditions happen 2 times within 60 minutes, indoor units’ Timer LED will blinks (“F91” is indicated at all indoor

units)

• This control detects 3-way valve close condition to prevent damage to refrigerant cycle.
• Start conditions:

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

°C and 2°C continu-

ously for 5 minutes after compressor ON at first cooling operation.

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

down.

• Control content

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

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

• This control protect by using high pressure switch during operation.
• Start conditions

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

compressor running.

• Control 1 content

- 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.

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

• Control 1 stop conditions

- Power supply reset
- Reset by using remote control

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• Operate the pump down process according to the following procedure

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

- Set the liquid side 3 way valve to close position and wait until the pressure gauge indicates 0.01Mpa (0.1kg/cm

2

G).

- 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.

 : 

Blinking

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

• 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.

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

LED

2

3

4

5

Message

S

tatu

s

Pump down operation in progress

3 minutes before operation end

2 minutes before operation end

1 minute before operation end

Pump down operation end