Mitsubishi Heat Pump
Controls and monitors Mitsubishi Ecodan heat pumps via Modbus RTU
Modbus RTU template for Mitsubishi Electric Ecodan heat pumps. Reads temperatures, energy data, flow rates, and error codes. Controls on/off, heating modes, DHW mode, and temperature setpoints via the MelcoBEMS MINI (A1M) interface.
- Protocol
- Modbus RTU
- Connection
- RS485, 9600 baud
- Registers
- 50, read and write
- Brand
- Mitsubishi Electric
- Key readings
- Flow and return temps (zones 1-2) · Tank water temp actual · Consumed and produced power · Energy consumption and production (day/month/year) · Flow rate · Error code digits 1-2
- Available commands
- Ecodan on/off · Tank water temp target · Zone 1 and Zone 2 thermostat setpoints · Heating mode Zone 1 and Zone 2
- Compatible models
- Ecodan
- Last updated
Registers (50)
48 read, 8 write
| Name | Unit | Access | Address (Hidden until you enter your email) | Function (hidden) | Type (hidden) |
|---|---|---|---|---|---|
| Flow Temp | °C | Read | |||
| Operating Mode DHW | Read and write | ||||
| Ecodan On-Off | Read and write | ||||
| Tank Water Temp Actual | °C | Read | |||
| Heating Mode – Zone 1 | Read and write | ||||
| Heating Mode – Zone 2 | Read and write | ||||
| Heat Pump On-Off | Read | ||||
| Return Temp | °C | Read | |||
| Flow Temp Zone 1 | °C | Read | |||
| Flow Temp Zone 2 | °C | Read | |||
| Return Temp Zone 1 | °C | Read | |||
| Return Temp Zone 2 | °C | Read | |||
| Water Pump 1 | Read | ||||
| Water Pump 2 | Read | ||||
| Flow Rate | l/min | Read | |||
| Last Measured Heating Consumption 1 | kWh | Read | |||
| Last Measured DHW Consumption 1 | kWh | Read | |||
| Energy Consumption Measured Day | Read | ||||
| Energy Consumption Measured Month | Read | ||||
| Energy Consumption Measured Year | Read | ||||
| Energy Production Measured Day | Read | ||||
| Energy Production Measured Month | Read | ||||
| Energy Production Measured Year | Read | ||||
| Last Measured Heating Production 1 | kWh | Read | |||
| Last Measured DHW Production 1 | kWh | Read | |||
| Consumed Power (actual) | kW | Read | |||
| Produced Power (actual) | kW | Read | |||
| Flow Temp Setpoint Zone 1 | °C | Read | |||
| Flow Temp Setpoint Zone 2 | °C | Read | |||
| Tank Water Temp Target | °C | Read and write | |||
| DHW Prohibited | Read | ||||
| Heating Zone 1 Prohibited | Read | ||||
| Heating Zone 2 Prohibited | Read | ||||
| DHW Temperature Drop | °C | Read | |||
| Last Measured DHW Consumption 2 | kW | Read | |||
| Last Measured Heating Consumption 2 | kW | Read | |||
| Last Measured DHW Production 2 | kW | Read | |||
| Last Measured Heating Production 2 | kW | Read | |||
| Display Error Code Digit 1 | Read | ||||
| Display Error Code Digit 2 | Read | ||||
| Booster Heater 1 | Read | ||||
| Booster Heater 2 | Read | ||||
| Water Pump 3 | Read | ||||
| Force DHW | Read and write | ||||
| Holiday | Read | ||||
| Legionella Prevention | Read | ||||
| Heat Source Phase DHW | Read | ||||
| Modbus Counter | Read | ||||
| Set Zone 1 Thermostat | °C | Write | |||
| Set Zone 2 Thermostat | °C | Write |
Loading registers…
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If a device is not in the library yet, we build the template for free as soon as we have the register data.
Use cases
- Monitor flow and return temperatures for Zone 1 and Zone 2 on a live cloud dashboard.
- Track daily, monthly, and yearly energy consumption and production to calculate heat pump COP remotely.
- Create an alert when an error code appears so you can respond before the end user notices a fault.
- Adjust DHW target temperature or force DHW operation remotely from the ModbusCloud interface.
- Log flow rate and power data over time to verify correct sizing and system performance for your customer.
- Switch heating modes per zone from the cloud to respond to changing occupancy or weather conditions.
Installation
Install the MelcoBEMS MINI (A1M) interface module on the Mitsubishi Ecodan heat pump according to the manufacturer instructions.
Connect the Modbus RTU wiring (A, B, GND) from the MelcoBEMS MINI to the RS-485 port on your ModbusCloud Gateway.
Set the Modbus slave address on the MelcoBEMS MINI interface and confirm the baud rate is 9600, 8N1.
Import the Mitsubishi Heat Pump template in the ModbusCloud platform and assign it to the correct gateway and slave address.
Verify communication by checking live values for flow temperature and tank water temperature on the ModbusCloud dashboard.
If multiple Ecodan units are on the same bus, ensure each MelcoBEMS MINI has a unique Modbus address and add a separate template instance per unit.
Things to watch for
Do I need additional hardware besides the Modbus gateway to connect to the Ecodan?
Yes. The MelcoBEMS MINI (A1M) interface module is required. It plugs into the heat pump and exposes the Modbus RTU registers. Without it, the heat pump has no Modbus capability.
What baud rate and serial settings should I use?
Use 9600 baud, 8 data bits, no parity, 1 stop bit (8N1). This is the default configuration for the MelcoBEMS MINI interface.
Can I both read and write setpoints with this template?
Yes. Several registers are bidirectional. You can read current values and write new targets for DHW mode, Ecodan on/off, heating modes, tank water temperature, and Force DHW.
Why do I see zero values for energy production or consumption counters?
The daily counter resets at midnight and may show zero shortly after. Monthly and yearly counters behave similarly. Confirm the heat pump has been running and that the correct register offsets are mapped to your slave address.
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