Defrost Operation Control - Fujitsu ASU18RLF Service Instructions Manual

20. DEFROST OPERATION CONTROL

1. CONDITION OF STARTING THE DEFROST OPERATION
The defrost operation starts as shown in the following Table 14, 15, and 16.
( Table 14 : Condition of 1st defrost operation)
1st defrost
after
starting operation
( Table 15 : Condition of 2nd defrost operation)
From 2nd and later
defrost after
starting operation
( Table 16 : Condition of Integrating defrost operation)
Integratingdefrost
(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 becomes as shown in Table 17.
( Table 17 : Condition of defrost release )
Outdoor heat exchanger temperature is higher than 55.4°F(13°C)
Compressor operation time has passed 15 minutes.
Compressor integrating operation time
Less than 22 minutes
Outdoor heat exchanger temperature
Does not operate
Compressor integrating operation time
Less than 35 minutes
Does not operate
Compressor integrating operation time
More than 210 minutes
( For long continuous operation )
Outdoor heat exchanger temperature
Below 26.6°F (-3°C)
Release Condition
or
More than 22 minutes
Below 15.8°F (-9°C )
More than 35 minutes
Outdoor heat exchanger temperature
Below 21.2°F (-6°C)
Less than 10 minutes
( For intermittent operation )
OFF count of the compressor
40 times
01-13
More than 62 minutes
Outdoor heat exchanger temperature
Below 23°F (-5°C )