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
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