Defrost Operation Control - Fujitsu ASU30RLE Service Instruction

1-30. DEFROST OPEARTION CONTROL
1. CONDITION OF STARTING THE DEFROST OPERATION
The defrost operation starts as shown in the following Table 23, 24, 25 and 26.
( Table 23 : Condition of 1st defrost operation )
1st defrost
after
starting operation
( Table 24 : Condition of 2nd defrost operation )
From 2nd and later
defrost after
starting operation
( Table 25 : Condition of Integrating defrost operation )
Integrating defrost
( Table 26 : Condition of Integrating ( OFF count ) defrost operation )
Integrating defrost
( OFF count defrost )
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. CONDITION OF THE DEFROST OPERATION COMPLETION
Defrost operation is released when the conditions becomes as shown in Table 27.
( Table 27 : Condition of defrost release )
Outdoor heat exchanger temperature is higher than
Compressor operation time has passed 15 minutes.
Compressor integrating operation time Compressor integrating operation time
Less than 17 minutes
Does not operate
(and after 5 minutes, in the 41°F(5°C))
Compressor integrating operation time
Less than 35 minutes
Does not operate
More than 210 minutes
( For long continuous operation )
Tn < 26.6°F(-3°C)
=
(and after 30 minutes, if the 26.6°F (-3°C))
Compressor integrating operation time
Less than 10 minutes
( For intermittent operation )
OFF count of the compressor : 40 times
Release Condition
or
More than 17 minutes
Tn < 15.8°F(-9°C)
=
and
Ta - Tn > 41°F(5°C)
=
Tn : Outdoor heat exchanger temperature.
Ta : Outdoor temperature.
More than 35 minutes
Tn < -77°F (-25°C)
①
=
②
Tn - Tn10 < -41°F (5°C) ( Tn < -42.8°F (6°C))
③ Tn - Tnb < -35.6°F (2°C) ( Tn < -42.8°F (6°C))
Tn10 : Temperature of continuous operation at 10 minutes.
Tnb : Back 5 minutes temperature.
Compressor integrating operation time
( For long continuous operation )
(and after 5 minutes, if the 23°F (-5°C))
55.4°F(13°C)
01-21
More than 57 minutes
Tn < 23°F(-5°C)
=
(and after 5 minutes, if the 23°F (-5°C))
=
=
More than 210 minutes
Tn < 23°F(-5°C)
=