This document serves as an Operation, Installation, and Maintenance Manual for HITACHI Inverter-Driven Multi-Split System Heat Pump Air Conditioners, specifically for indoor units of the RPI-FSNQ and RPI-FSN3Q series (8.0 HP and 10.0 HP models). It is crucial to read and understand this manual before using the heat pump air conditioners and to keep it for future reference.
Function Description
The HITACHI heat pump air conditioner is designed for standard air conditioning, offering cooling, heating, dry, and fan operations. These modes are controlled by an optional remote control switch. The system supports a maximum total capacity of 130% and a minimum total capacity of 50% when combining indoor units.
The system incorporates several automatic control functions to optimize performance and ensure safety:
- Three Minute Guard (Enforced Stoppage/Operation): The compressor remains off for at least 3 minutes after stopping to prevent rapid cycling. If the system is started within 3 minutes of stopping, the RUN indicator activates, but cooling or heating operations will only commence after the 3-minute delay. Conversely, if all indoor units are in Thermo-OFF within 3 minutes of compressor start-up, the compressor will operate continuously for 3 minutes. However, if all indoor units are stopped by the remote control switch, the compressor will stop.
- Oil Return Operation: If an indoor unit is stopped for more than 2 continuous hours, this function activates for a few minutes to prevent refrigerant oil from accumulating in the heat exchanger of the stopped unit during cooling operation.
- Frost Prevention During Cooling Operation: To prevent frost formation on the indoor heat exchanger, the cooling operation may temporarily switch to fan operation if the indoor unit operates at a low discharge air temperature.
- Hot Start During Heating Operation: To prevent cold air discharge into the room, the fan speed is controlled from slow to low, and then to the set position, based on the discharge air temperature. The louver is fixed horizontally during this process.
- Slow Air Control During Defrosting Operation: When the outdoor unit performs automatic defrosting, the indoor fan stops, and the louver is fixed horizontally.
- Cooling of Indoor Unit: After heating operation stops, the indoor fan continues to operate at a slow speed for up to 2 minutes to lower the internal unit temperature.
- Automatic Defrosting Cycle: When heating operation is stopped by pressing the RUN/STOP switch, the system checks for frosting on the outdoor unit and may perform a defrosting operation for a maximum of 10 minutes.
- Prevention of Overload Operation: If the outdoor temperature is high during heating operation, the system will stop heating due to the activation of the outdoor thermistor until the temperature drops.
Usage Features
The remote control switch, which can control up to 16 indoor units, features touching-type switches. Users should press switches only with fingers to avoid damage. The temperature setting increases by 1 degree with each press of the TEMP switch, with a minimum setting of 17°C and a maximum of 30°C. The set temperature refers to the air temperature at the indoor unit's sensor, which may differ from the actual room temperature due to sensing location variations.
For optimal operation, the room should be ventilated every 3 to 4 hours. If the system is started after a shutdown longer than approximately 3 months, it is recommended to have it checked by a service contractor. When the system is stopped for a long period, the main switch should be turned OFF to conserve electricity, as the oil heater remains energized during compressor stoppage.
Maintenance Features
The manual emphasizes several maintenance-related checks and precautions:
- Initial Check: Upon receiving the product, inspect it for shipping damage and verify the model number, electrical characteristics, and accessories.
- Troubleshooting: If issues arise, the manual provides guidance. For instance, if drain water overflows, stop operation and contact a contractor. If white smoke or unusual smells occur, turn off the main power supply and contact a contractor. Common issues like "Not Cooling or Heating Well" can often be resolved by checking for airflow obstructions, excessive heat sources, clogged air filters, or open doors/windows. The manual also clarifies that certain sounds (from deforming parts or refrigerant flow), steam from the outdoor heat exchanger during defrosting, and dew on the air panel under high humidity conditions are not abnormal. If trouble persists after these checks, users should contact their contractor, providing the unit model name, content of trouble, and any alarm code displayed.
- Electrical Wiring: Before any electrical wiring work or periodical checks, the main power switch to both indoor and outdoor units must be turned OFF, and fans must have stopped. Wires, drain pipes, and electrical parts must be protected from pests like rats to prevent damage or fire. Screws should be tightened to specified torques (M3.5: 1.2 N-m, M5: 2.0~2.4 N-m). The wiring connection hole should be plugged with seal material to protect against condensate water or insects.
- Test Run: A test run should be performed according to the "Installation & Maintenance Manual" of the outdoor unit. Before operating the system, ensure all check points are cleared, including verifying electrical resistance (more than 1 megohm), fully opening outdoor unit stop valves, and ensuring the main power source has been ON for over 12 hours to warm the compressor oil. During operation, avoid touching hot parts at the discharge gas side (which can exceed 90°C) and do not push the buttons of magnetic switches, as this can cause serious accidents.
- Drain Piping: After drain piping and electrical wiring, ensure water flows smoothly by pouring 2 to 2.5 liters of water into the drain pan and checking for leakage. If water is not found at the end of the drain piping, pour another 2 liters.
- Dip Switch Settings: Before setting dip switches, the power source must be turned OFF. Setting switches without turning off the power source will prevent them from functioning.
The manual also includes important safety notices, such as not pouring water into units, not touching or adjusting safety devices, and not opening service covers without turning off the main power supply. It warns against refrigerant leakage and the use of flammable sprays near the system. The appliance is not to be used by children or persons with reduced physical, sensory, or mental capabilities without supervision. It should not be installed in a laundry room. Proper disposal of the product is also highlighted, emphasizing recycling to promote sustainable reuse of materials.
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