Mitsubishi Electric PUHY-P200 Service Handbook page 74

6. Refrigerant recovery control
• Recovery of refrigerant is performed during heating operation to prevent the refrigerant from accumulating
inside the unit while it is stopped (unit in fan mode), or inside the indoor unit that is in cooling mode or in heat-
ing mode with thermo off.
It is also performed during cooling operation to prevent an excessive amount of refrigerant from accumulating
in the outdoor heat exchanger.
[During heating operation]
(1) Initiation of refrigerant recovery
• Recovery of refrigerant during heating operation begins when all of the following three conditions are met:
1 15 minutes have past since the completion of previous refrigerant recovery.
2 Td >105˚C (P200 type), 115˚C (P250-P650)
3 Frequencies below 50 Hz
(2) Refrigerant recovery
• Refrigerant is recovered with the LEV on the
applicable indoor unit (unit under stopping mode,
fan mode, cooling, heating with thermo off) being
opened for 30 seconds.
• Periodic capacity control of the outdoor units and
periodic LEV control of the indoor units will be suspended during refrigerant recovery operation; they will be
performed after the recovery has been completed.
• Defrost operation will be suspended until refrigerant recovery has been completed.
[During cooling operation]
(1) Initiation of refrigerant recovery
• Recovery of refrigerant during cooling operation begins when all of the following conditions are met:
1 30 minutes have past since the completion of previous refrigerant recovery.
2 When discharge temperature has remained above the limit continuously.
3 Td > 95˚C (P200 type), 105˚C (P250-P650) or [Pd > 3.43MPa (35kg/cm
(2) Refrigerant recovery
• Increase the opening of LEV1 (Periodic control begins when 30 seconds have elapsed).
7. Outdoor unit fan
(1) Control method
• The air volume of outdoor unit fan is controlled by the inverter control to maintain a constant evaporation
temperature (0˚C = 0.71 MPa) during cooling operation and constant condensing temperature
(49˚C = 2.88MPa) during heating operation, depending on the required capacity.
• The capacity of the outdoor unit heat exchanger is controlled by the 4-way valve (21S4b, 21S4c) or the sole-
noid valve (SV5b, SV5c) (21S4c and SV5c for P400-P650 types only).
(2) Control
• Outdoor unit fan stops while the compressor is stopped (except when there is an input from snow sensor).
• The fan operates at full speed for 5 seconds after start up (except the units with high static pressure specifi-
cations).
• The outdoor unit fan stops during defrost operation.
Opening of LEV during refrigerant recovery
(Opening of indoor unit LEV: 400 pulses)
Initial opening of LEV
- 72 -
30 seconds
Start Finish
G and SC0 >10deg)]
2