Panasonic Heat Pumps: manuals, user guides and error codes
Looking for a Panasonic 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 Panasonic 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:
- WH-MDC05J3E5
- WH-MDC07J3E5
- WH-MDC09J3E5
- WH-MDC12J6E5
- WH-MDC16J9E5
- WH-MXC09J3E5
- WH-MXC12J6E5
- WH-MXC16J9E5
- WH-MDC05H3E5
- WH-MDC09H3E5
- WH-MDC12H6E5
- WH-MDC16H6E5
- S2125-20
- S2125-8
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Heat pump malfunctions: Panasonic 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 |
| H00 | No Fault | System operating normally; no active error. |
| H11 | Indoor-Outdoor Communication Fault | Communication error between indoor and outdoor units; check wiring and connections. |
| H12 | Capacity Mismatch Fault | Indoor and outdoor unit mismatch or incorrect configuration. |
| H14 | Indoor Air Temperature Sensor Fault | Fault with indoor air temperature sensor. |
| H15 | Outdoor Compressor Temperature Sensor Fault | Compressor temperature sensor failure. |
| H16 | Current Transformer Fault | Electrical current detection fault. |
| H19 | Indoor Fan Motor Lock | Indoor fan motor not rotating or obstructed. |
| H23 | Indoor Heat Exchanger Sensor Fault | Fault with indoor coil temperature sensor. |
| H24 | Indoor Heat Exchanger Sensor Fault (Secondary) | Secondary indoor coil sensor failure. |
| H25 | Air Ion / Air Quality Fault | Fault with air purification system (if fitted). |
| H26 | External Device Fault | Fault triggered by external control or accessory. |
| H27 | Outdoor Air Temperature Sensor Fault | External air sensor failure; affects system efficiency. |
| H28 | Outdoor Heat Exchanger Sensor Fault | Outdoor coil sensor fault. |
| H29 | Outdoor Pipe Temperature Sensor Fault | Fault with refrigerant pipe sensor. |
| H30 | Discharge Temperature Sensor Fault | Compressor discharge sensor failure. |
| H31 | Room Temperature Sensor Fault | Room sensor failure or incorrect reading. |
| H32 | Outlet Water Temperature Sensor Fault | Water flow temperature sensor fault. |
| H33 | Inlet Water Temperature Sensor Fault | Return water sensor fault. |
| H34 | Outdoor Heat Sink Sensor Fault | Fault with inverter heat sink temperature sensor. |
| H35 | Indoor / Outdoor Connection Fault | Incorrect wiring or system connection error. |
| H36 | Water Flow Switch Fault | No water circulation detected; possible pump or airlock issue. |
| H37 | Water Pump Fault | Circulation pump not operating correctly. |
| H38 | Water Pressure Fault | System pressure too low or high; check filling loop or expansion vessel. |
| H39 | Defrost Fault | Defrost cycle not operating correctly. |
| H41 | Freeze Protection Activated | System protecting against freezing conditions. |
| H42 | Water Temperature Too High | Flow temperature exceeded safe limits. |
| H43 | Low Water Temperature Fault | Water temperature too low; may indicate system imbalance. |
| H50 | Ventilation Fan Fault | Ventilation or auxiliary fan failure. |
| H51 | Overload Protection Fault | System overloaded; compressor or electrical issue. |
| H52 | Voltage Supply Fault | Supply voltage outside acceptable limits. |
| H59 | Indoor Unit Communication Fault | Internal communication error within indoor unit. |
| F90 | Compressor Overload Protection | Compressor operating outside safe limits. |
| F91 | Refrigeration Cycle Fault | General refrigerant circuit issue. |
| F92 | Compressor Discharge Temperature High | Compressor overheating; possible flow or refrigerant issue. |
| F93 | Compressor Abnormal Rotation | Compressor not operating correctly. |
| F95 | High Pressure Protection | Refrigerant pressure too high; poor heat transfer or flow issue. |
| F96 | Power Transistor Module Overheat | Inverter module overheating. |
| F97 | Compressor Overheat Protection | Compressor temperature exceeded safe limit. |
| F98 | Total Current Protection | Excess electrical current detected. |
| F99 | DC Peak Current Fault | Electrical surge or inverter issue. |
| U02 | Power Supply Fault | Voltage too high or low; unstable power supply. |
| U03 | Communication Fault (Wiring) | Communication wiring issue between components. |
| U04 | Communication Fault (Indoor-Outdoor) | Loss of communication between units. |
| U07 | Communication Fault (Controller) | Remote controller communication issue. |
| U10 | Data Transmission Fault | Internal data communication error. |
| U12 | Addressing Fault | Incorrect system addressing or configuration. |
| U14 | Sensor Communication Fault | Sensor data transmission error. |
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.


