Ras-8/10Fxg - Hitachi FSG1 Series Technical Catalogue

CONTROL SYSTEM
9
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9.1.3.

RAS-8/10FXG

Control Subject
Fan Revolution of Outdoor Unit
Opening Degree of Exp. V for
Liquid Bypass: MVB
Opening Degree of Exp. V of
Outdoor Unit: MV1, MV2
Opening Degree of Exp. V of
Indoor Unit: MV
Inverter Frequency of
Compressor
Exp. V: Micro-Computer Control Expansion Valve
Figure below shows the outline of the control system.
Thermistor for Inlet Air
Wireless Remote
Thermistor of Discharge Air
Control Switch
Thermistor of Gas Pipe
Remote
Control
MCU
Wireless Transmission
A+D
Circuit
Conversion
Circuit
Remote Control Switch
Indoor Unit
Remote
Control
MCU
MCU
Electrical Control
Relay Drive
Fan
Expansion Valve
Control
Circuit
Drive Circuit
Indoor Unit
Symbol
MC Motor (for Compressor)
MIF Motor (for Indoor Fan)
MOF Motor (for Outdoor Fan)
MS Motor (for Auto-Louver)
MV1,2,B Electronic Expansion Valve
THR Fin Thermostat
EHW Electric Heater
Cooling Operation
For Controlling Discharge Pressure: Pd
(Main Control for Pd)
For Controlling Temperature of Discharge Super-
Heat: Td SH
For Controlling Pressure: Pd (Sub Control for Pd)
1 For Controlling Temperature Difference between
air Inlet and air Outlet of Indoor Unit
2 For Controlling Temperature Difference between
Gas Pipe and Liquid Pipe of Indoor Unit Heat
Exchanger
For Controlling Pressure of Refrigerant Suction: PS
Thermistor of Liquid Pipe
CH Unit
MCU
Relay
Protection
Drive
Circuit
Circuit
To Transmission Circuit to the
next Unit of the same CH-Unit
Purpose
Heating Operation
For Controlling Pressure based on Outdoor air
Temperature
Closed
For Controlling Temperature of Discharge Super-
Heat: Td SH
1 For Controlling Temperature Difference between
air Inlet and air Outlet of Indoor Unit
2 For Balancing Temperature Differences between
Gas Pipe and Liquid Pipe of each Indoor Unit
For Controlling Pressure of Refrigerant discharge:
Pd
Suction Gas Pressure Sensor
Discharge Gas Pressure Sensor
Thermistor of Atmospheric Air
Discharge Gas Thermistor
Thermistor for Heating Evaporation Temperature
A+D Conversion
Circuit
Outdoor Unit
MCU
Electrical Control
Relay Drive
Expansion Valve Drive
Circuit
Circuit
To Transmission Circuit of the
next CH Unit or Outdoor Unit
(H-Link)
Symbol Name
CMC Magnetic Contactor
RVR 4-Way Valve
SVa,b, c Solenoid Valve (for Gas Bypass)
PSH Pressure Switch
CT1,2 Current Transformer
SVS1,2 Solenoid Valve
SVD1,2 Solenoid Valve (DC)
Multiple Signals
Single Signals
Operation Signals
380/415V Power
Source
Protection
Circuit
Inverter Power
Inverter
Section
Control MCU
Outdoor Unit