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W-2WAY ECO-i SYSTEM
Control Functions
Defrost
outdoor unit
Evaporator
outdoor unit
Evaporator
outdoor unit
Evaporator
outdoor unit
Evaporator
outdoor unit
Defrost
outdoor unit
Defrost
outdoor unit
Defrost
outdoor unit
Defrost
outdoor unit
Evaporator
outdoor unit
First operation
Second operation
First operation
Second operation
Switch
Switch
(2) Defrost sequence
Outdoor unit cycle defrost is always completed in 2 defrost operations.
(A) When there are 2 outdoor units
(B) When there are 3 outdoor units
• Defrost flow
E: Evaporator operation
C: Condenser operation
S: Shut off
E
→
C: Switching from evaporator operation to condenser operation
C
→
E: Switching from condenser operation to evaporator operation
OFF
ON
ON
ON
EE
ON
C
C
C
C
OFF
E
CC
CC
OFF
S
S
SS
S
S
S
SS
S
C
C
C
ON
C
E
→
C
E
→
C
OFF
OFF
E or S
C
→
E or S
C
→
E
Stopped indoor unit(s)
Indoor units where fan is operating
Heating mode indoor
units
Time
Defrost
preparation
Defrost in
progress
Defrost in
progress
Defrost
end
judgment
Defrost
end
judgment
1 min
1 min
1 min
Max. 6 min
Max. 6 min
Thermostat ON
Thermostat OFF
Outdoor unit(s) where defrost occurs first
Outdoor compressor(s) where defrost occurs first
Outdoor unit(s) where defrost follows later
Outdoor compressor(s) where defrost follows later
Switch
Defrost
preparation
4-3-6. Outdoor unit cycle defrost
Outdoor unit cycle defrost is performed in systems where 2 or more outdoor units are connected to the refrigerant
system.
(1) Description of outdoor unit cycle defrost
With this defrost method, when 1 outdoor unit operates in defrost mode (heat exchanger operating as a con-
denser), another outdoor unit operates as an evaporator in the same way as in ordinary heating mode. In this
way, the other outdoor unit is heating the unit where defrost is occurring. When 1 outdoor unit completes defrost,
the other outdoor unit performs defrost in the same way. Because the amount of time that the unit operates as an
evaporator is very short, there is little danger of frost forming again quickly. Rather, because the heat source is
very powerful, it is possible to shorten the defrost operating time.
4. Special Controls
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