Fujitsu AOTG36LATT, Service Manual

Page: 129 / 264

23. 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 Table19.
2. CONDITION OF THE DEFROST OPERATION COMPLETION
Defrost operation is released when the conditions become as shown in Table 20.
( Table 20 : Defrost Release Condition )
Release Condition
Outdoor heat exchanger temperature sensor value is higher than +13°C.
or Compressor operation time has passed 15 minutes.
( Table 19 : Condition of starting Defrost Operation )
1 time defrosting
after starting operation
ST
Defrosting after 2 time
upon starting operation
ND
Compressor integrating operation time
Compressor integrating operation time
Compressor integrating operation time
Less than 22 min. 22 to 62 min. More than 62 min.
Does not operate
- 9°C - 5°C
Less than 35 min. More than 35min.
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 215 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,
the OFF number of the compressor is counted.
If any defrost operated, the compressor OFF count is cleared.
Tn-Tn10 < - 5deg
Tn-Tnb < - 2deg
However, Tn < - 6°C
=
Tn10 : Temperature of continuous operation at 10minutes.
Tnb : Back 5minutes temperature