Defrost Operation Control - Fujitsu AS*G09KXCA Series 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 Table15.
( Table 15 : Condition of starting Defrost Operation )
Defrosting (Normal)
starting operation
Tn10 : Temperature of continuous operation at 10minutes.
Tnb : Back 5minutes temperature
Integrating defrost
(Constant monitoring)
*1 : If the compressor continuous operation time is less than 10 min, 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 Table16.
( Table16 : Defrost Release Condition )
Outdoor heat exchanger temperature sensor value is higher than
+16°C or Compressor operation time has passed 15min.
Compressor integrating operation time
Less than 40min.
Tn < - 17°C
Does not operate
Tn-Tn10 < - 5deg
Tn-Tnb < - 2deg
However, Tn < - 6°C
Compressor integrating operation time
More than 240min.
(For long continuous operation)
- 3°C
Release Condition
More than 40min.
=
=
More than 215min.
(For long continuous operation)
- 5°C
01-16
Less than 10min.*1
(For intermittent operation)
OFF count of the compressor
40 times.