6. Defrost operation control
Tn: Outdoor unit heat exchanger temperature
Ta: Outdoor temperature
Tn10: Temperature at 10 minutes after compressor start
Tnb: Temperature before 5 minutes
•
Triggering condition
The defrost operation starts when outdoor unit heat exchanger temperature sensor detects the
temperature lower than the values shown below.
–
1st time defrosting after starting operation
Compressor integrating
operation time
Less than 17 min.
17 to 57 min.
More than 57 min.
Condition
Does not operate
Tn ≤ -9°C and Tn-Ta ≥ 5
deg
Tn ≤ -5°C
–
2nd time and after
Compressor integrating
operation time
Less than 35 min.
More than 35 min.
Condition
Does not operate
Tn-Tn10 < -5 deg (Tn ≤ -10°C )
Tn-Tnb < -2 deg (Tn ≤ -10°C )
Tn ≤ -25°C (Ta ≥ -20°C)
Tn ≤ Ta-7°C or Tn ≤ -25°C (Ta < -20°C)
–
Integrating defrost (Constant monitoring)
Compressor integrating
operation time
More than 240 min. (For
long continuous
operation)
More than 215 min. (For
long continuous
operation
Less than 10 min.* (For
intermittent operation)
Condition
Tn ≤ -3°C
Tn ≤ -5°C
Count of the compressor
off: 40 times
*: If the compressor continuous operation time is less than 10 minutes, the number of the com-
pressor 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)
12°C or more
Compressor operation time
15 minutes
- (01-28) -
6. Defrost operation control
CONTROL AND
FUNCTIONS
CONTROL AND
FUNCTIONS