II - 6
Processes and Functions
SM830063
2
¶
Defrost is accomplished through a reverse-cycle operation.
¶
During defrost operation, the outdoor fan is stopped and the indoor fan is either stopped or run at L or LL.
2-1. Frost detection
(1)
Frost is not monitored for the first 1 minutes of operation.
(2)
The frost detection conditions are:
Condition 1 = heat exchanger liquid temp. is 8 minutes continuously below the L2 line
Condition 2 = heat exchanger liquid temp. is 60 minutes, cumulative, below the L1 line
2. Reverse Cycle Defrosting
–25
–23
–10
The area below the heavy lines is
the frost detection area.
L2
L1
–3
–21.4
–8
–1
10
10
Outdoor temperature
°
C
1245_M_I
Heat exchange liquid temperature
°
C
Defrost
end temperature
This end temperature differs
from the frost detection
temperature above.
Control sections
2-2. Defrost execution condition
(1)
35 minutes or more, cumulative, for heating operation. (The cumulative time differs depending on the outside air
temperature and the maximum condensing temperature.)
2-3. Defrost end conditions
(1)
Outdoor heat exchanger liquid temperature
]
10 ˚C
(2)
Defrost operation is 12 minutes maximum.
(3)
Reverse-cycle defrost control
One minute
During reverse-cycle operation
One minute after
before defrosting
(12 minutes max.)
completion of defrosting
P/C compressor
OFF
Compressor capacity control
OFF
AC compressor
OFF
↑
OFF
4-way valve
ON
OFF
ON
Outdoor fan
STOP
STOP
H
Low-pressure valve 1, 2, 3
ON
Compressor capacity control
ON
High-pressure valve
OFF
↑
OFF
Save valve
ON
Save valve control
ON
Outdoor electronic expansion valve
0 pulses
480 pulses
0 pulses
Operation of each control section in defrosting
