Hitachi Heat Pumps: manuals, user guides and error codes
Looking for a Hitachi heat pump manual, user guide, or error code explanation? ServiceMy has created a dedicated resource hub to help homeowners quickly find the information they need for their system.
Our guide library includes downloadable manuals, setup instructions, troubleshooting advice and clear explanations of common error codes. If your Hitachi heat pump is showing a fault code, not heating properly, or you simply want to understand how to operate it more efficiently, our guides are designed to help you identify the issue and keep your system running smoothly. These resources are regularly updated and written by experienced heat pump engineers to help you get the most from your heating system, improve efficiency and avoid unnecessary breakdowns.
These apply for the following air source heat pump models:
- RAS-2WHVNP
- RAS-2.5WHVNP
- RAS-3WHVNP
- RAS-4WH(V)NP
- RAS-5WH(V)NP
- RAS-6WH(V)NP
- RAS-8WHVNP
- RAS-10WHVNP
- RASM-4VNE
- RASM-6VNE
- RASM-8VNE
- RASM-12VNE
- RASM-16VNE
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Heat pump malfunctions: Hitachi Error Codes
If you cannot find the error code explanation or need help resolving any issues, ServiceMy can help diagnose and arrange a professional heat pump service to restore your system to optimum performance.
| Error Code | Title | Explanation |
| 1 | High Pressure Fault | Refrigerant pressure too high; often due to poor water flow, blocked heat exchanger, or airflow restriction. |
| 2 | Low Pressure Fault | Refrigerant pressure too low; typically caused by leaks, low charge, or airflow issues. |
| 3 | Compressor Discharge Temperature Fault | Compressor temperature too high; may indicate low flow, refrigerant imbalance, or excessive load. |
| 4 | Outdoor Air Temperature Sensor Fault | External sensor failure; affects system control and efficiency. |
| 5 | Water Flow Temperature Sensor Fault | Flow sensor fault; impacts heating regulation and system performance. |
| 6 | Return Temperature Sensor Fault | Return sensor failure; may lead to incorrect modulation. |
| 7 | Domestic Hot Water Sensor Fault | Cylinder temperature sensor fault affecting hot water production. |
| 8 | Evaporator Coil Sensor Fault | Coil temperature sensor failure; affects defrost cycle. |
| 9 | Condenser Temperature Sensor Fault | Heat exchanger sensor fault; impacts safe operation. |
| 10 | Water Flow Fault | Insufficient water circulation; commonly pump failure, airlock, or blockage. |
| 11 | Low Water Pressure Fault | System pressure too low; check filling loop, leaks, or expansion vessel. |
| 12 | High Water Temperature Fault | Water temperature exceeded safe limits; often caused by poor circulation. |
| 13 | Defrost Fault | Defrost cycle failure; likely airflow restriction or sensor issue. |
| 14 | Communication Fault | Internal communication error between PCB components. |
| 15 | Inverter / Compressor Drive Fault | Fault with inverter board controlling compressor operation. |
| 16 | Fan Motor Fault | Outdoor fan failure; affects heat exchange and performance. |
| 17 | Anti-Freeze Protection Active | System protecting against freezing due to low temperatures. |
| 18 | Refrigerant Circuit Fault | General refrigerant system fault requiring further diagnostics. |
| 19 | Pressure Sensor Fault | Fault with pressure sensor; may give incorrect readings. |
| 20 | Control Board Fault | Internal PCB or electronics failure. |
| 21 | Overcurrent Protection Fault | Electrical overcurrent detected; possible compressor or wiring issue. |
| 22 | Voltage Supply Fault | Power supply outside acceptable range. |
| 23 | Circulation Pump Fault | Pump failure or not operating correctly. |
| 24 | Flow Switch Fault | No water movement detected; indicates circulation issue. |
| 25 | High Condensing Temperature | Condenser temperature too high; poor heat transfer or flow issue. |
| 26 | Low Evaporating Temperature | Evaporator temperature too low; possible airflow restriction or refrigerant issue. |
| 27 | 4-Way Valve Fault | Reversing valve failure affecting heating/defrost operation. |
| 28 | Defrost Sensor Fault | Sensor responsible for defrost cycle has failed. |
| 29 | Discharge Temperature Sensor Fault | Compressor discharge sensor failure. |
| 30 | System Configuration Fault | Incorrect setup or parameter mismatch within system. |
| 31 | Room Thermistor Fault | Indoor room temperature sensor failure. |
| 32 | Suction Temperature Sensor Fault | Refrigerant suction sensor fault. |
| 33 | Liquid Line Sensor Fault | Liquid refrigerant line sensor failure. |
| 34 | Heat Sink Overheat Fault | Inverter heat sink temperature too high. |
| 35 | Compressor Lock Fault | Compressor unable to start or seized. |
| 36 | EEPROM Fault | Internal memory or configuration error in control board. |
| 37 | Communication Fault (Indoor-Outdoor) | Communication failure between indoor and outdoor units. |
| 38 | Communication Fault (Controller) | Remote controller communication issue. |
| 39 | System Addressing Fault | Incorrect addressing or system configuration mismatch. |
Schedule Your Heat Pump Service Today
Don’t wait until efficiency drops, or your pump encounters issues. Investing in routine maintenance for your air source heat pump is the best way to keep your household energy-efficient, cosy, and cost-effective year-round.
Get in touch with our professional servicing team today to schedule your appointment. With extensive experience in heat pump servicing and home energy solutions, we’re here to help you stay warm, save money, and protect your investment.
Maintain your heat pump, and it will reward you with years of efficient and reliable performance.
