Hitachi RAS-8.0HNBRMQ1 - Page 56

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(2) Model: RAS-7.0~12HNBRMQ1
Symbol PCB Purpose
PCB1
Outdoor Unit Board
(Main Board)
1. Communicating between Indoor Unit and Outdoor Unit;
2. Processing Sensor Input;
3. Processing DIP Switch Input;
4. Operation Control for Above Items 1 to 3. Compressor Operation Control, Fan Control,
Expansion Valve, 4-Way Valve, Solenoid Valve, and Overcurrent Control;
5. 7-Segment Indication;
6. Processing of Safety Device Input;
7. Processing of Relay Output;
8. Reverse Phase Detection for Power Source.
PCB2
Driver Board
(for Inverter)
1. Compressor is driven by Driver Board;
2. Overcurrent Control;
3. Protection Control.
PCB3 Fan Motor Driver Board
1. Fan motors are driven by Fan Motor Driver Board;
2. Overcurrent Control;
3. Protection Control.
NF1 Noise Filter Board
1.Filt the Clutter of the Power Source
2.Prevent the harmonic from damaging the Power Source
TROUBLESHOOTING