Defrost Operation Control - Fujitsu AB A30LBT Series Service Instruction

1-21. DEFROST OPERATION CONTROL

1. CONDITION OF STARTING THE DEFROST OPERATION
The defrost operation starts as shown in the following Table 10.
(Table 10 : Condition of starting Defrost Operation)
1st defrost after
starting operation
From 2nd and later
defrost after
starting operation
Integrating defrost
(Constant monitoring)
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 11.
(Table 11 : Defrost Release Condition)
Outdoor heat exchanger temperature sensor value is higher than +13°C or
Compressor operation time has passed 15 minutes.
Less than 22 minutes
Does not operate
Compressor integrating operation time
Less than 35 minutes
Does not operate
Compressor integrating operation time
More than 240 minutes
(For long continuous operation)
Outdoor heat exchanger
temperature below -3°C
Release Condition
Compressor integrating operation time
More than 22 minutes
Outdoor heat exchanger
temperature Below -9°C
More than 35 minutes
Outdoor heat exchanger
temperature below -6°C
Less than 10 minutes
( For intermittent operation )
OFF count of the compressor
40 times
01-19
More than 62 minutes
Outdoor heat exchanger
temperature Below -5°C