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4. Special Controls
4-3-3. Frost detection
(A) Frost detection does not occur for 5 minutes after operation starts.
(B) Frost is detected when either condition 1 or 2 below is met.
Condition 1: L2 line or below is detected twice, each time continuously for 4 minutes, when the compressor is
operating.
Condition 2: L1 line or below is detected for a total of 60 minutes when the compressor is operating.
–6.5
4-3-4. Outdoor units where defrost occurs
Even if the total time has not reached 35 minutes, if there is 1 or more outdoor units that fulfills the defrost
detection conditions, all operating outdoor units perform defrost control at the same time.
* Defrost control is also performed at outdoor units where the outdoor unit heat exchanger is not functioning as an
evaporator (such as stopped outdoor units).
4-3-5. Reverse cycle defrost
Reverse cycle defrost is performed in systems where only 1 outdoor unit is connected to the refrigerant system.
• Defrost flow
E: Evaporator operation
C: Condenser operation
E→C: Switching from evaporator operation to condenser operation
C→E: Switching from condenser operation to evaporator operation
Outdoor unit status
Stopped indoor units
Indoor units where fan is operating
Cooling mode
Thermostat ON
indoor units
Thermostat OFF
Heating mode
Thermostat ON
indoor units
Thermostat OFF
Compressor
Time
* With type D, E → C occurs for 3 minutes after defrost ends. Therefore the thermostat remains OFF for 3
minutes.
Heat exchange liquid temperature ˚F
Defrosting operation
42.8
end temperature
50
30
26
17
14
The frost detection area is
located under the thick lines
–9
–13
Defrost preparation
E → C
E → C
E
E
E
E
E
E
E
E
C → E
C → E
C → E
C → E
Stopped
Operating
1 min
1 min
1 - 13
(The end temperature is different from
the above detection temperature.)
External temperature ˚F
L1
L2
Defrost in progress
Defrost end
C → E
C
E
E
Defrost
E
end
E
judgment
E → C
E
E → C
E
Operating
Stopped
Max. 12 min
1 min
3-WAY ECO-i SYSTEM
Control Functions
E
E
E
E
1
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