Defrost Operation Control - Fujitsu ARU7RLF Service Instruction

21. 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 17-1, 17-2, 17-3.
1-1 NORMAL DEFROST
For AOU18 / 24RLXFZ
(Table 17-1 : Condition of starting defrost operation)
Normal defrost
For AOU36RLXFZ
(Table 17-2 : Condition of starting defrost operation)
Normal defrost
1-2. INTEGRATING DEFROST
For AOU18 / 24 / 36RLXFZ
(Table 17-3 : Condition of starting defrost operation)
Integrating defrost
If the compressor continuous operation time is less than 10 minutes,
the OFF number of the compressor is counted.
If any defrost operated, the compressor OFF count is cleared.
2. CONDITION OF THE DEFROST OPERATION COMPLETION
Defrost operation is released when the conditions become as shown in Table 18-1, 18-2.
For AOU18 / 24RLXFZ
(Table 18-1 : Defrost release condition)
Outdoor heat exchanger temperature sensor value is higher than 50.0°F(10°C) or
Compressor operation time has passed 15 minutes.
For AOU36RLXFZ
(Table 18-2 : Defrost release condition)
Outdoor heat exchanger temperature sensor value is higher than 53.3°F(12°C) or
Compressor operation time has passed 15 minutes.
Compressor integrating
operation :Less than 45min.
Less than 6 min. *1
Does not operate
Compressor integrating
operation :Less than 45min. Less than 6 min. *1
Does not operate
Compressor integrating operation time
More than 210 minutes
(For continuous operation)
When the compressor is
stopped, If detected
outside air temp. at 35.6°F(2°C)
Release Condition
Release Condition
Compressor integrating
operation :45min and over
After 6 min. *1
or 10min. *2
or 10min. *2
17.6°F(-8°C) *3
10.3°F(-12°C) *4
6.8°F(-14°C) *5
3.2°F(-16°C) *6
Compressor integrating
operation :45min and over
After 6 min. *1
or 10min. *2 or 10min. *2
14.0°F(-10°C) *3
10.4°F(-12°C) *4
Less than 10 minutes
( For intermittent operation )
OFF count of the compressor
40 times
( at outside air temp. < 35.6°F(2°C)
01-26
*1. It means contiguous operation time.
*2. Compressor stop time:
Below 20min. Select 6min.
Above 20min. Select 10min.
*3. Outdoor temp. > 37.4°F(3°C)
*4. Outdoor temp. > 30.2°F(-1°C)
*5. Outdoor temp. > 23.0°F(-5°C)
*6. Outdoor temp. < 23.0°F(-5°C)
=
*1. It means contiguous operation time.
*2. Compressor stop time:
Below 20min. Select 6min.
Above 20min. Select 10min.
*3. Outdoor temp. > 30.2°F(-1°C)
*4. Outdoor temp. < 30.2°F(-1°C)
=