Service manual

SiE18-201
Main Functions 55
Part 5
Main Functions
OutdoorUnit / BP Unit
1. Refrigerant System and Function of Functional Parts of Outdoor Unit .57
1.1 Refrigerant System and Function of Functional Parts of Outdoor Unit.. 57
1.2 Major Functional Parts........................................................................... 58
1.3 Protective Devices, Thermistors, Sensors............................................. 60
2. Protection Device..................................................................................61
2.1 Outdoor Unit .......................................................................................... 61
2.2 BP Unit .................................................................................................. 62
3. System control ......................................................................................63
3.1 Outline of System Control...................................................................... 63
3.2 Mode Configuration ............................................................................... 64
3.3 Standby Control at Power ON ............................................................... 65
3.4 Cooling / Heating Standby Operation at Startup ................................... 66
3.5 Equalizing Control ................................................................................. 67
3.6 Determination of Initial Frequency......................................................... 69
3.7 Oil Return Operation.............................................................................. 74
3.8 Defrost Operation .................................................................................. 76
3.9 Pre-Equalization Standby Operation ..................................................... 77
3.10 Equalizing Control ................................................................................. 78
3.11 Capacity Control.................................................................................... 80
3.12 Peak Cut Control ................................................................................... 82
3.13 Freeze-Up Prevention ........................................................................... 83
3.14 Gas Shortage Malfunction..................................................................... 84
3.15 Discharge Pipe Control.......................................................................... 85
3.16 Input Current Control............................................................................. 86
3.17 Wet Protection Control I ........................................................................ 89
3.18 Electric Parts Cooling and Electric Parts / Fin Temperature Control..... 90
3.19 Differential Pressure Control ................................................................. 91
3.20 Year-Round Cooling-Only Function....................................................... 92
3.21 Nighttime Low Noise Control................................................................. 93
3.22 PI Control............................................................................................... 94
3.23 Warm-Up Function ................................................................................ 95
3.24 Compressor Protection Control ............................................................. 96
3.25 Fan Control............................................................................................ 97
3.26 Motorized Valve Control of Outdoor Unit............................................... 99
3.27 Cooling Outdoor Unit SC Control ........................................................ 105
3.28 BP Unit Motorized Valve Control......................................................... 106
3.29 Gas Pipe Isothermal Control in Cooling Operation.............................. 109
3.30 SH Control in Cooling Operation ......................................................... 111
3.31 SC Control in Heating Operation......................................................... 113
3.32 Heat Exchanger Isothermal Control in Heating Operation .................. 115
3.33 BP Unit Motorized Valve Control in High Discharge
Pipe Temperature................................................................................ 116
3.34 Inter-BP Units Heating Heat Exchanger Isothermal Control................ 117