YES
YES
YES
YES
YES
NO
NO
NO
NO
NO
Heating operation
Defrost
operation
4-way valve OFF
Test run start
Thermostat
ON
3-minute
restart prevention
Normal operation
Trouble observed
Stop
Test run
4-way valve OFF
Notes :
❉
1 When outdoor unit starts defrosting, it transmits defrost operations command to indoor unit, and BC controller and the indoor
unit starts defrosting operations.
Similarly when defrosting operation stops, indoor unit returns to heating operation after receiving defrost end command of
outdoor unit.
1. Indoor unit fan stop
2. Inverter defrost frequency
control
3. Indoor unit LEV fully closed
4. Solenoid valve control
5. Outdoor unit fan stop
6. LEV1 control
7. 52C1 control
Defrost end
Defrost end
Return to
heating operation
Note:
❉
1, 2
Note:
❉
1, 2
1. Indoor unit fan very low
speed operation
2. Inverter output 0Hz
3. Indoor unit LEV, BC LEV
fully closed
4. Solenoid valve all OFF
5. Outdoor unit fan stop
6. 52C1 OFF
7. BC SV OFF
1. Indoor and outdoor unit fan
control
2. Inverter frequency control
3. Indoor unit LEV, BC LEV
control
4. Solenoid valve control
5. 52C1 control
6. BC SV control
❉
2 Defrost ending condition : Defrost operation for 10 minutes or more, or outdoor piping temperature : refer to “5. Defrost operation
control” of [2] ControlIing the Outdoor Unit.
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(2) Heating operation