Mitsubishi Electric PUHY-P200 Service Handbook page 81

(2) Heating operation
1. Indoor unit fan very low
speed operation
2. Inverter output 0Hz
3. Indoor unit LEV, LEV1 fully
closed
4. Solenoid valve all OFF
5. Outdoor unit fan stop
6. 52C1 OFF
Notes :
❉1 When outdoor unit starts defrosting, it transmits defrost operations command to indoor unit, 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.
❉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.
Heating operation
Note: ❉1, 2
YES
Defrost
operation
NO
4-way valve OFF
YES
Test run start
NO
NO
Thermostat
ON
YES
YES
3-minute
restart prevention
NO
1. Indoor and outdoor unit fan
control
2. Inverter frequency control
3. Indoor unit LEV, LEV1
control
4. Solenoid valve control
5. 52C1 control
4-way valve OFF
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
heating operation
- 79 -
Normal operation
Trouble observed
Stop
Test run
Note: ❉1, 2
NO
Defrost end
YES
Defrost end
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