Fujitsu AOU18RLB, Service Instructions Manual

Page: 19 / 71

23. DEFROST OPERATION CONTROL
1. CONDITION OF STARTING THE DEFROST OPERATION
The defrost operation starts as shown in the following Table 19 .
2. CONDITION OF THE DEFROST OPERATION COMPLETION
Release Condition
Outdoor heat exchanger temperature sensor value is higher than 60.8
°F(
16°C) or
Compressor operation time has passed 15 minutes.
( Table 19 : Condition of starting defrost operation )
Defrost operation is released when the conditions become as shown in Table 20 .
( Table 20 : Defrost release condition )
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.
Integrating defrost
Normal defrost
Compressor integrating operation time
Less than 40 minutes (
AOU18RLB
)
Less than 40 minutes (
AOU24RLB
)
More than 40 minutes (
AOU18RLB
)
More than 40 minutes (
AOU24RLB
)
Does not operate
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))
More than 240 minutes
(For continuous operation)
Less than 10 minutes
( For intermittent operation )
Compressor integrating operation time
Outdoor heat exchanger
temperature below 26.6°F(-3°C)
More than 213 minutes
(For continuous operation)
Outdoor heat exchanger
temperature below 23°F(-5°C)
OFF count of the compressor
40 times
=
=
=
=
=
=
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))
=
01-16