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2WAY SYSTEM
Control Functions
-
Outdoor Unit
1
- 30
1
9. Defrost Control
OFF
N
O
N
O
ON
E
E
ON
C
C
C
C
OFF
E
C
C
C
C
OFF
S
S
S
S
S
S
S
S
S
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
1 min
5 min
1 min
5 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
9-7. Outdoor unit cycle defrost
Outdoor unit cycle defrost is performed in systems where 2 or more outdoor units are connected to the
refrigerant system.
9-7-1. Description of outdoor unit cycle defrost
In this defrosting, the outdoor units are devided into two groups. When outdoor units in the first defrosting
group operate in defrost mode (heat exchanger operating as a condenser), outdoor units in the second
defronting group operates as an evaporator in the same way as in ordinary heating mode. In this way, outdoor
units in the second defronting group supply heat to the unit where defrost is occurring. When outdoor units in
the first defrosting group completes defrost, the other outdoor unit performs defrost in the same way.
9-7-2. Defrost sequence
Outdoor unit cycle defrost is always completed in 2 defrost operations.
- When there are 2 outdoor units
- 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
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
Second operation
First operation
Second operation
First operation
Switch
Switch
SM830186-00̲2WAY ECO-i.indb 30
SM830186-00̲2WAY ECO-i.indb 30
2010/12/24 10:09:58
2010/12/24 10:09:58