Defrost Operation Control - Fujitsu AMUG24LMAS Service Manual

11. DEFROST OPERATION CONTROL

1. CONDITION OF STARTING DEFROST OPERATION
Defrost operation starts as below.
AOU24/30RGLX
(1st defrost after starting operation)
Compressor
integrating
operation time
Condition
AOU24/30RGLX
(2nd defrost or later after staring operation)
Compressor
integrating
operation time
AOU24, 30RGLX,
Condition
AOUG36/48LMAS1
Normal defrost
Less than 35 minutes
Does not operate
Tn : Outdoor heat-exchanger temperature.
Ta : Outside temperature.
Tn-1 : Before 5 minutes detected Tn.
Condition of Integrating defrost operation
Compressor
integrating
operation time
Condition
Integrating (OFF count) defrost operation
Compressor
integrating
operation time
Condition
2. CONDITION OF THE DEFROST OPERATION COMPLETION
Defrost operation is released when conditions become as below.
AOU24/30RGLX
AOUG36/48LMAS1
Less than
More than 17 minutes
17 minutes
Does not work
(and after 5 minutes, if 41°F (5°C))
Less than
35 minutes
①
Does not work
②
③
Compressor integrating operation time
< =
Tn
(at Ta
< =
Tn
(at 4°F (-20°C) < = Ta < 14°F (-10°C)
< =
Tn
(at Ta < 4°F (-20°C))
Tn - Tn-1
(Tn 21.2°F (-6°C))
More than 210 minutes
( For long continuous operation )
Tn ≤ 26.6°F (-3°C)
(and after 30 minutes, if 26.6°F (-3°C))
Less than 10 minutes
(For intermittent operation)
OFF count of compressor : 40 times
Outdoor heat-exchanger temperature is higher than 55.4°F (13°C)
or Compressor operation time has passed 15 minutes.
Outdoor heat-exchanger temperature is higher than 59.0°F (15°C)
or Compressor operation time has passed 15 minutes.
Tn : Outdoor heat-exchanger temperature.
Ta : Outside temperature.
Tn10 : Temperature of continuous operation at 10 minutes.
Tnb : Back 5 minutes temperature.
Tn ≤ 15.8°F (-9°C)
and
Ta - Tn ≥ 41°F (5°C)
More than 35 minutes
Tn ≤ -13°F (-25°C)
Tn - Tn10 < 9°F (-5°C) ( Tn ≤ 21.2°F (-6°C))
Tn - Tnb < -3.6°F (-2°C) ( Tn ≤ 21.2°F (-6°C))
More than 35 minutes
1.4°F (-17°C)
> = 14°F (-10°C)
< =
0.8 x Ta-11.6 or Tn -18.4 °F
< =
0.8 x Ta-11.6 or Tn -18.4 °F
< 28.4°F (-2°C)
More than 210 minutes
(For long continuous operation)
Tn ≤ 23°F (-5°C)
(and after 5 minutes, if 23°F (-5°C))
If 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.
04-25
More than 57 minutes
Tn ≤ 23°F (-5°C)
(and after 5 minutes, if 23°F (-5°C))
(-28°C)
(-28°C)