Defrost Operation In Heating Operation Stopped - Fujitsu ACUH09LUAS1 Service Manual

– Models: AOUH12LUAS1 and AOUH18LUAS1
• 1st time defrosting after starting operation
Compressor integrating
operation time
Condition
• 2nd time and after
Compressor integrating
operation time
Condition
• Integrating defrost (Constant monitoring)
Compressor integrating
operation time
Condition
*: If the compressor continuous operation time is less than 10 minutes, the number of the
compressor off is counted. If any defrost operated, the compressor off count is cleared.
Release condition
•
The defrost operation is released when either one of the conditions below is satisfied.
Outdoor unit heat exchanger temperature
(after 1 minute or later since compressor start)
Compressor operation time

6-1. Defrost operation in heating operation stopped

If the outdoor unit is frosted when stopping the heating operation, it stops after performing the auto-
matic defrosting operation.
In this time, if the indoor unit operation lamp flashes slowly (6 sec on/2 sec off), the outdoor unit al-
low the heat exchanger to defrost, and then stop.
Triggering condition
•
→hen all of the following conditions are satisfied in heating operation
– Compressor operation integrating time: 30 minutes or more
– Compressor continuous operation time: 10 minutes or more
– Outdoor unit heat exchanger temperature: 24.8°F (-4°C) or less
Release condition
•
The defrost operation is released when either one of the conditions below is satisfied.
Outdoor unit heat exchanger temperature
(after 1 minute or later since compressor start)
Compressor operation time
6-1. Defrost operation in heating operation stopped
Less than 17 min.
Does not operate
Less than 40 min.
Does not operate
More than 240 min. (For
long continuous
operation)
Tn ≤ 26.6°F (-3°C)
12/18 model
12/18 model
- (04-24) -
17 to 57 min.
Tn ≤ 15.8°F (-9°C) and
Tn-Ta ≥ 9.0°F (5°C)
More than 40 min.
Tn-Tn10 < -9.0°F (-5°C) (Tn ≤ 21.2°F [-6°C])
Tn-Tnb < -3.6°F (-2°C) (Tn ≤ 21.2°F [-6°C])
Tn ≤ -4.0°F (-20°C) (Ta ≥ 14.0°F [-10°C])
Tn ≤ 19.4°F (-7°C) or Tn ≤ -13.0°F (-25°C) (Ta <
14.0°F [-10°C])
More than 213 min. (For
long continuous
operation
Tn ≤ 23.0°F (-5°C)
09 model 60.8°F (16°C) or more
55.4°F (13°C) or more
09 model 60.8°F (16°C) or more
55.4°F (13°C) or more
More than 57 min.
Tn ≤ 23.0°F (-5°C)
Less than 10 min.* (For
intermittent operation)
Count of the compressor
off: 40 times
15 minutes
15 minutes
6. Defrost operation control