Hitachi RAS-25CNH1

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– 93 –

Be sure to replace

the rainproof cover

after checking

(rainwater would

enter if it is not

installed).

R inproof cover

(transparent)

Main Page

Table of Contents1
Specifications1
Room Air Conditioner1
Technical Information1
Service Manual1
Safety During Repair Work2
Working Standards for Preventing Breakage of Semiconductors3
Object Parts3
Items to be Observed in Handling3
Conductive Container3
Grounding of the Working Table4
Grounding a Soldering Iron4
Caution5
Specifications6
- Direction of Piping7
- Dimension of Mounting Stand of the Outdoor Unit7
- The Length of Indoor Unit Connecting Cord7
- Precautions During Shifting or Maintenance8
- Precautions During Operation8
- Precautions During Installation8
Safety Precaution8
- Names and Functions of each Part10
- Indoor Unit10
- Outdoor Unit10
- Operation Indicator11
- Indoor Unit Indicators11
- Names and Functions of Remote Control Unit12
- Remote Controller12
- Precautions for Use12
- Condition of Automatic Operation13
- Automatic Operation13
- Heating Operation14
- Dehumidifying Operation15
- Dehumidifying Function15
- Cooling Operation16
- Fan Operation17
- Fan Speed (Auto)17
- How to Set the Timer18
- How to Cancel Reservation18
- Time, Day, Month18
- OFF-Timer18
- How to Set the Sleep Timer20
- Operation with the Sleep Timer21
- Explanation of the Sleep Timer21
- Adjusting the Air Deflector22
- Adjustment of the Conditioned Air to the Left and Right22
- How to Exchange the Batteries in the Remote Controller23
- Temporary Switch23
- The Ideal Ways of Operation24
- Suitable Room Temperature24
- Install Curtain or Blinds24
- Ventilation24
- When Lightning Occurs25
- For User’s Information25
- Not Operating for a Long Time25
- The Air Conditioner and the Heat Source in the Room25
- Attaching the Air Cleansing and Deodorizing Filters26
- Maintenance27
- Air Filter27
- Washable Front Panel28
- Removing the Front Panel28
- Attaching the Front Panel28
- Maintenance at Beginning of Long off Period29
- Regular Inspection29
- When Asking for Service, Check the Following Points30
- Notes30
Construction and Dimensional Diagram31
- Thermostat32
- Thermostat Specifications32
- Fan Motor Specifications32
Main Parts Component32
- Compressor Motor Specifications33
- Compressor Motor33
Wiring Diagram34
Circuit Diagram35
Block Diagram37
Room Temp. Shift Value38
Basic Mode38
- Basic Cooling Operation40
- Dehumidifying41
- Cooling Defrost41
- Cool Rhythm42
- Twmax43
- Speed Specification During Fixed Rotation Period43
- Basic Heating Operation43
- Reversing Valve Defrost44
Auto Swing Function45
Reset Circuit46
Description of Main Circuit Operation46
- Receive Circuit47
- Buzzer Circuit47
- Buzzer Operation47
- Auto Sweep Motor Rotation48
- Auto Sweep Motor Circuit48
- Micro Computer Output Signals48
- Auto Sweep Motor Circuit (Horizontal Air Deflectors)48
- Room Temperature Thermistor Circuit49
- Heat Exchanger Temperature Thermistor Circuit49
- DC Fan Motor Drive Circuit50
- Fan Motor Set Wind Velocity and DC Voltage51
- Characteristics51
- 12V Power Circuit52
- Diode Stacks53
- Reactor and Power Capacitor53
- Power Circuit53
- DC Voltmeter or Teste54
- Smoothing Capacitor54
- Inrush Protective Resistor54
- Indoor/Outdoor Interface Circuit55
- Voltages Waveforms of Indoor / Outdoor Micro Computers57
- Power Module Circuit58
- Switching Order of Power Module59
- Voltage Waveform at each Point59
- Power Module Circuit (U + Is ON, V – Is ON)60
- Power Circuit for P.W.B.61
- Shifting from off to on61
- During on Period62
- Shifting from on to off62
- During off Period62
- When Power Circuit for P.W.B. Is Estimated as Abnormal63
- Abnormal Only When Output of 5V Voltage Has Decreased63
- When 12V and 5V Voltage Are Abnormal63
- Reversing Valve Control Circuit64
- Rotor Magnetic Pole Position Detection Circuit65
- Forward Current Waveform at Point a66
- Upper Arm Drive Circuit66
- Drive Circuit66
- Waveform of Transistor Base Current67
- Lower Arm Drive Circuit68
- HIC and Peripheral Circuits69
- Micro Computer(AX-8E21) and Peripheral Circuits69
- Peak Current Cut off Circuit and Waveforms at each Section70
- Overload Control Circuit71
- Overload Control System Configuration71
- Voltage Amp. Circuit72
- During Overload Control72
- During Start Current Control73
- Circuits to Which Trip Signals Are Transferred74
- Trip Signal Synthesis Circuit74
- Temperature Detection Circuit75
- Cooling77
- Heating77
Refrigerating Cycle Diagram77
Service Call Q & a78
- Auto Operation80
- Wireless Remote Controller81
- Common/Others81
- Precautions for Checking82
Trouble Shooting82
- Discharging Capacitors83
- Cutting off Power Supplied to the Power Circuit83
- Trouble Shooting When the Timer86
- Dehumidifying Lamp Blinks86
- Only the Indoor Unit Fan Does Not Operate91
- The Fan Speed of the Indoor Unit Fan Cannot be Changed91
- The Air Deflector Cannot be Moved92
- Operation Completely Stops Within a few Seconds Minutes after Starting92
- Is Battery Polarity Right?93
- Chekcing the Remote Control Switch93
- Using a Video Monitor94
- Using a Checker94
- Using the Test Card94
- Method for Diagnosis of Power Module101
- How to Check Power Module102
- Checking Power Module Using Tester102
- Checking the Refrigerating Cycle103
- Troubleshooting Procedure103
Parts List and Diagram104

Hitachi RAS-25CNH1 - Page 84

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