Brand: HITACHI
Category: Air Conditioner
Document Type: Manual
Language: EN
Manual for RAS-18YH6/RAC-18YH6
Uploaded: Nov. 21, 2025, 8:57 p.m.
Manual Publish Date: 2006-12-01
This manual provides technical information for the HITACHI RAS-18YH6/RAC-18YH6 and RAS-25YH6/RAC-25YH6 air conditioners. It covers specifications, construction diagrams, main parts, wiring and circuit diagrams, basic mode operation, troubleshooting, disassembly/reassembly procedures, and parts lists. Safety precautions for repair work, handling semiconductors, and general cautions during operation are also detailed. Specific sections explain various functions like automatic operation, heating, cooling, dehumidifying, fan operation, and timer programming. Detailed instructions are provided for adjusting air deflectors and exchanging remote controller batteries. Maintenance procedures, including air filter cleaning and front panel cleaning, are also included. The manual also details troubleshooting procedures based on self-diagnosis lamp blinking codes and checks for the refrigerating cycle and intelligent power modules (IPM). It concludes with procedures for using the service switch and operating the outdoor unit independently, along with a comprehensive parts list for both indoor and outdoor units.
Troubleshooting and error codes
| CONDITION | CHECK THE FOLLOWING POINTS |
| If the remote controller is not transmitting a signal. (Remote controller display is dim or blank.) | Do the batteries need replacement? Is the polarity of the inserted batteries correct? |
| When it does not operate. | Is the fuse all right? Is the voltage extremely high or low? Is the circuit breaker "ON"? Is the power plug inserted? Do you have any power cut? |
| When it does not cool well. | Is the air filter blocked with dust? Is the set temperature suitable? Have horizontal air deflectors been adjusted to their correct positions according to the operation mode selected? Are the air inlets or air outlets of indoor and outdoor units blocked? |
| When it does not heat well. | Is the fan speed "LOW"? Are the air inlets or air outlets of indoor and outdoor units blocked? |