Defrost Operation Control - Fujitsu ASU18RLB Service Instructions Manual

23. DEFROST OPERATION CONTROL

1. CONDITION OF STARTING THE DEFROST OPERATION
The defrost operation starts as shown in the following Table 19 .
( Table 19 : Condition of starting defrost operation )
Normal defrost
Integrating 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 become as shown in Table 20 .
( Table 20 : Defrost release condition )
Outdoor heat exchanger temperature sensor value is higher than 60.8
Compressor operation time has passed 15 minutes.
Less than 40 minutes (
AOU18RLB
Less than 40 minutes (
AOU24RLB
Does not operate
More than 240 minutes
(For continuous operation)
Outdoor heat exchanger
temperature below 26.6°F(-3°C)
Release Condition
Compressor integrating operation time
) More than 40 minutes (
) More than 40 minutes (
Outdoor heat exchanger temp. < 1.4°F(-17°C)
(at outside air temp. > 14°F(-10°C)
=
Outdoor heat exchanger temp. < Outside air temp.-(12.6°F (7°C))
or Outdoor heat exchanger temp.< -13°F (-25°C)
(at -4°F (-20°C)< Outdoor air temp.< 14°F (-10°C))
=
Outdoor heat exchanger temp. < Outside air temp.-(12.6°F (7°C))
or Outdoor heat exchanger temp. < -22°F(- 30°C)
(at outside air temp. < -4°F(-20°C))
Compressor integrating operation time
More than 213 minutes
(For continuous operation)
Outdoor heat exchanger
temperature below 23°F(-5°C)
01-16
AOU18RLB
AOU24RLB
=
=
=
=
=
Less than 10 minutes
( For intermittent operation )
OFF count of the compressor
40 times
16°C) or
°F(
)
)