Pump Down ( Refrigerant Collecting Operation ); Compressor Preheating; Defrost Operation Control - Fujitsu ABU18RULX Service Instruction

15. PUMP DOWN ( Refrigerant collecting operation )

Perform the following procedures to collect the refrigerant when moving the indoor unit or the outdoor unit.
When the product is stopped:
1. Press the PUMP DOWN switch (SW2) on the outdoor unit.
(The LED on the outdoor unit circuit board flickers every 1second.)
2. The pump down operation (cooling operation) begins right away.
After operation starts, close the 3-way valve (liquid).
3. After 2-3minutes, operation stops. Close the 3-way valve (gas) within 1minute after operations stops.
4. The LED will go out 3minutes after it stops. Disconnect the power supply after confirming that the LED has gone out.
When the product is operating:
1. Press the PUMP DOWN switch (SW2) on the outdoor unit. The LED on the outdoor unit circuit board flickers
every 1second, and operation stops.
At this point, recovery has not been completed, so do not close the 2 and 3-way valves.
2. The pump down operation (cooling operation) begins after 3minutes.
Close the 3-way valve (liquid) after operation starts.
3. After 2-3minutes, operation stops. Close the 3-way valve (gas) within 1minute after operations stops.
4. The LED will go out 3minutes after it stops. Disconnect the power supply after confirming that the LED has gone out.

16. COMPRESSOR PREHEATING

When the outdoor heat exchanger temperature is lower than Operation temperature (Refer to Table 8) and the heating
operation has been stopped for 3 hours, power is applied to the compressor and the compressor is heated.
(By heating the compressor, warm air is quickly discharged when operation is started.)
When operation was started, and when the outdoor temperature rises to Release temperature or greater,
preheating is over.
(Table 8 : Preheating Operation / Release Temperature)
ABU18RULX
ABU24RULX
ABU36RSLX

17. DEFROST OPERATION CONTROL

1. CONDITION OF STARTING THE DEFROST OPERATION
The defrost operation starts when the outdoor heat exchanger temperature sensor detects
the temperature lower than the values shown in Table 9.
(Table 9 : Condition of starting Defrost Operation)
Compressor integrating
operation :Less than 45min.
ABU18RULX
ABU24RULX
ABU36RSLX
*1. It means contiguous operation time.
*2. Compressor stop time: Below 20min.
2. CONDITION OF THE DEFROST OPERATION COMPLETION
Defrost operation is released when the conditions become as shown in Table 10.
(Table 10 : Defrost Release Condition)
ABU18RULX
ABU24RULX
ABU36RSLX
Before 24 hour
Operation Release
temperature temperature
37.4°F 44.6°F
(3°C) (7°C)
Compressor integrating
operation :45min and over
Less than 6 min. *1
or 10min. *2
Does not operate
Above 20min.
Outdoor heat exchanger temperature sensor value is higher than 53.6°F(12°C) or
Compressor operation time has passed 15 minutes.
After 24 hour
Operation Release
temperature temperature
32°F 39.2°F
(0°C) (4°C)
After 6 min. *1
or 10min. *2
° °
17.6 F(-8 C) *3
° °
14 F (-10 C) *4
*3. Outdoor temp. > 30.2°F (-1°C)
*4. Outdoor temp. < 30.2°F (-1°C)
Select 6min.
Select 10min.
Release Condition
01-16
=