Fujitsu AO*G18LFC series, Service Instruction

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20. DEFROST OPERATION CONTROL
01-15
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 Table16.
2. CONDITION OF THE DEFROST OPERATION COMPLETION
Defrost operation is released when the conditions become as shown in Table17.
( Table17 : Defrost Release Condition )
Release Condition
Outdoor heat exchanger temperature sensor value is higher than +16°C
or
Compressor operation time has passed 15 minutes.
( Table 16 : Condition of starting Defrost Operation )
Normal defrost
Compressor integrating operation time
Compressor integrating operation time
Less than 25 min. More than 25min.
Does not operate
Integrating defrost
(Constant monitoring)
More than 240 min.
(For long continuous operation) Less than 10min.*1
(For intermittent operation)
- 3°C
More than 213 min.
(For long continuous operation)
- 5°C
OFF count of the compressor
40 times.
*1 : If the compressor continuous operation time is less than 10 minutes and outdoor air temperature is less than 2°C
once while operating the compressor, the OFF number of the compressor is counted.
If any defrost operated, the compressor OFF count is cleared.
Tn-Tn10< - 5deg, Tn < - 6°C
Tn-Tnb < - 2deg, Tn < - 6°C
Tn < - 17°C, Ta > - 10°C
Tn-Ta < - 7deg, Ta < - 10°C
Tn < - 20°C
=
=
=
=
=
=
Tn10 : Temperature of continuous operation at 10minutes.
Tnb : Back 5minutes temperature
Ta : Outside air temperature