SiBE31-801_C Normal OperationFunction 966.6 Control for Heating Operation at Low Outdoor AirTemperatureTo conduct optimal heating operation, the two operation modes, "Two-stage compression" and"Single-stage compression", are available according to outdoor temperatures and loads.System startupDetermination of operation mode*Determine at startup whether to conduct single-stage compression or two-stage compression.&· Outdoor temp. < 5°C· Capacity of indoor unitwith thermostat ON> 7.1 to 11.2kWOR· Outdoor temp. ≥ 5°C· Capacity of indoor unitwith thermostat ON≤ 7.1 to 11.2kWTwo-stage compressionOR· Outdoor temp. ≥ 7°C· &· Pc > 3.3MPa· Function unit compressor = 52Hz· Outdoor unit compressor< 104Hz + OFF + OFF· When (Indoor unit operating capacity ×Function unit compressor operating capacity)comes less than a certain valueSingle-stage compression&· Outdoor temp. < 5°C· Capacity of indoor unitwith thermostat ON> 7.1 to 11.2 kW· Outdoor unit compressor> 112Hz + OFF + OFF· A lapse of 2 min.
