Defrost Operation Control - Fujitsu AS* G09LECB Service Instruction

21. DEFROST OPERATION CONTROL

1. CONDITION OF STARTING THE DEFROST OPERATION
The defrost operation starts when the outdoor heat exchanger temperature sensor (Tn) detects
the temperature lower than the values shown in Table 18.
(Table 18 : Condition of starting Defrost Operation)
Normal defrost
Integrating defrost
2. CONDITION OF THE DEFROST OPERATION COMPLETION
Defrost operation is released when the conditions become as shown in Table 19.
(Table 19 : Defrost Release Condition)
Outdoor heat exchanger temperature sensor value is higher than +16°C or
Compressor operation time has passed 15 minutes.
Compressor integrating operation time
Less than 35 minutes
Does not operate
More than 240 minutes
(For continuous operation)
Outdoor heat exchanger
temperature below -3°C
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.
Release Condition
01-16
More than 35 minutes
Tn < -17°C (at outside air temp. > -10°C)
=
Tn < Outside air temp.- 7°C
=
or Tn < - 20°C
=
(at -20°C < outside air temp. < -10°C)
=
Tn < Outside air temp.- 7°C
=
or Tn < - 30°C
=
(at outside air temp. < -20°C)
Tn -Tn10 < -5deg
Tn -Tnb < -2deg
However, Tn < -6°C
=
Tn10 : Temperature of continuous operation at 10 minutes.
Tnb : Back 5 minutes temperature
Compressor integrating operation time
More than 213 minutes
(For continuous operation)
Outdoor heat exchanger
temperature below -5°C
=
Less than 10 minutes
( For intermittent operation )
OFF count of the compressor
40 times