Daikin FTX25JVEA9 Service Manual page 5

Part 5 Main Functions Outdoor Unit / BP Unit.......................... 101
1. Refrigerant System and Function of Functional Parts
2. Protection Device ................................................................................107
3. System control ....................................................................................109
iv
of Outdoor Unit....................................................................................103
1.1 Refrigerant System and Function of Functional Parts
of Outdoor Unit .....................................................................................103
1.2 Major Functional Parts .........................................................................104
1.3 Protective Devices, Thermistors, Sensors ...........................................106
2.1 Outdoor Unit .........................................................................................107
2.2 BP Unit .................................................................................................108
3.1 Outline of System Control ....................................................................109
3.2 Mode Configuration ..............................................................................110
3.3 Standby Control at Power ON ..............................................................111
3.4 Cooling / Heating Standby Operation at Startup ..................................112
3.5 Equalizing Control ................................................................................113
3.6 Determination of Initial Frequency........................................................115
3.7 Oil Return Operation ............................................................................120
3.8 Defrost Operation .................................................................................122
3.9 Pre-Equalization Standby Operation ....................................................123
3.10 Equalizing Control ................................................................................124
3.11 Capacity Control...................................................................................126
3.12 Peak Cut Control ..................................................................................128
3.13 Freeze-Up Prevention ..........................................................................129
3.14 Gas Shortage Malfunction....................................................................130
3.15 Discharge Pipe Control ........................................................................131
3.16 Input Current Control............................................................................132
3.17 Wet Protection Control I .......................................................................135
3.18 Electric Parts Cooling and Electric Parts /
Fin Temperature Control ......................................................................136
3.19 Differential Pressure Control ................................................................137
3.20 Year-Round Cooling-Only Function .....................................................138
3.21 Nighttime Low Noise Control................................................................139
3.22 PI Control .............................................................................................140
3.23 Warm-Up Function ...............................................................................141
3.24 Compressor Protection Control ............................................................142
3.25 Fan Control...........................................................................................143
3.26 Motorized Valve Control of Outdoor Unit..............................................145
3.27 Cooling Outdoor Unit SC Control .........................................................151
3.28 BP Unit Motorized Valve Control..........................................................152
3.29 Gas Pipe Isothermal Control in Cooling Operation ..............................155
3.30 SH Control in Cooling Operation ..........................................................157
3.31 SC Control in Heating Operation..........................................................159
3.32 Heat Exchanger Isothermal Control in Heating Operation ...................161
3.33 BP Unit Motorized Valve Control in High Discharge
Pipe Temperature.................................................................................162
3.34 Inter-BP Units Heating Heat Exchanger Isothermal Control ................163
3.35 Inter-BP Units Gas Pipe Isothermal Control.........................................164
3.36 BP Unit Motorized Valve Control by Target Discharge
Pipe Temperature.................................................................................165
3.37 4-Way Valve Operation ........................................................................166
Si18-201
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