Defrost Operation Control - Fujitsu AU G18LVLB Series Service Instruction

1-22. DEFROST OPERATION CONTROL

1. CONDI T I O N OF STARTI N G THE DEFROST OPERATI O N
The defrost operation starts when the outdoor heat exchanger temperature sensor (Tn) detects
the temperature lower than the values shown in Table11.
( Table 11 : Condition of starting Defrost Operation )
1 time defrosting
ST
after starting operation
Defrosting after 2
ND
upon 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 minutes,
the OFF number of the compressor is counted.
If any defrost operated, the compressor OFF count is cleared.
2. CONDI T I O N OF THE DEFROST OPERATI O N COMPLETI O N
Defrost operation is released when the conditions become as shown in Table12.
( Table12 : Defrost Release Condition )
Outdoor heat exchanger temperature sensor value is higher than
+13°C or Compressor operation time has passed 15 minutes.
Compressor integrating operation time
Less than 22 min.
Does not operate
Compressor integrating operation time
time
Less than 40 min.
Does not operate
Compressor integrating operation time
More than 240 min.
(For long continuous operation)
- 3°C
Release Condition
22 to 62 min. More than 62 min.
- 9°C
More than 40min.
Tn-Tn10 < - 5deg
Tn-Tnb < - 2deg
However, Tn < - 6°C
=
Less than 10min.*1
(For intermittent operation)
OFF count of the compressor
40 times.
01-20
- 5°C