Midea M-Thermal
Air to water heat pump that reports water temperatures, compressor data and faults and takes setpoints.
The Midea M-Thermal is an air to water heat pump that heats and cools homes and small buildings and makes domestic hot water. This Modbus RTU template reads water and outdoor temperatures, compressor data, water flow and fault codes, and lets you switch zones and hot water on or off and set the mode and setpoints from ModbusCloud.
- Protocol
- Modbus RTU
- Connection
- RS485, 9600 baud
- Registers
- 114, read and write
- Brand
- Midea
- Key readings
- Water outlet temperature · Water inlet temperature · Outdoor temperature · DHW tank temperature · Compressor frequency · Water flow · Current fault · Operating mode
- Available commands
- Power on or off · Operating mode · Water temperature setpoint · Room temperature setpoint · DHW setpoint · Forced backup heater
- Compatible models
- M-Thermal wired controller · Midea M-Thermal air to water heat pumps (split and mono) with the M-Thermal wired controller and Modbus terminals H1 and H2
- Last updated
Registers (114)
114 read, 11 write
| Name | Unit | Access | Address (Hidden until you enter your email) | Function (hidden) | Type (hidden) |
|---|---|---|---|---|---|
| Compressor Frequency | Hz | Read | |||
| Operating Mode | Read | ||||
| Fan Speed | rpm | Read | |||
| EEV Opening | Read | ||||
| Water Inlet Temperature | °C | Read | |||
| Water Outlet Temperature | °C | Read | |||
| Condenser Temperature T3 | °C | Read | |||
| Outdoor Temperature T4 | °C | Read | |||
| Discharge Temperature | °C | Read | |||
| Suction Temperature | °C | Read | |||
| Total Water Outlet Temperature T1 | °C | Read | |||
| Water Outlet After Backup Heater T1B | °C | Read | |||
| Refrigerant Liquid Temperature T2 | °C | Read | |||
| Refrigerant Gas Temperature T2B | °C | Read | |||
| Room Temperature Ta | °C | Read | |||
| DHW Tank Temperature T5 | °C | Read | |||
| High Pressure | kPa | Read | |||
| Low Pressure | kPa | Read | |||
| Outdoor Unit Current | A | Read | |||
| Outdoor Unit Voltage | V | Read | |||
| Hydraulic Module Current 1 | A | Read | |||
| Hydraulic Module Current 2 | A | Read | |||
| Compressor Operating Hours | h | Read | |||
| Current Fault | Read | ||||
| Fault 1 | Read | ||||
| Fault 2 | Read | ||||
| Fault 3 | Read | ||||
| Status Bits | Read | ||||
| Load Outputs | Read | ||||
| Unit Version | Read | ||||
| Wired Controller Version | Read | ||||
| Compressor Target Frequency | Hz | Read | |||
| DC Bus Current | A | Read | |||
| DC Bus Voltage | V | Read | |||
| Inverter Module Temperature | °C | Read | |||
| Zone 1 Calculated Setpoint | °C | Read | |||
| Zone 2 Calculated Setpoint | °C | Read | |||
| Water Flow | m³/h | Read | |||
| Current Limit Scheme | Read | ||||
| Hydraulic Module Capacity | kW | Read | |||
| Power On Off | Read and write | ||||
| Mode Setting | Read and write | ||||
| Water Temperature Setpoint T1s | °C | Read and write | |||
| Room Temperature Setpoint Ts | °C | Read and write | |||
| DHW Setpoint T5s | °C | Read and write | |||
| Function Setting | Read and write | ||||
| Curve Selection | Read and write | ||||
| Forced Water Heating | Read and write | ||||
| Forced TBH | Read and write | ||||
| Forced IBH1 | Read and write | ||||
| Smart Grid Max Time | h | Read and write | |||
| Appliance Type | Read | ||||
| T1S Cooling Upper Limit | °C | Read | |||
| T1S Cooling Lower Limit | °C | Read | |||
| T1S Heating Upper Limit | °C | Read | |||
| T1S Heating Lower Limit | °C | Read | |||
| Room Setpoint Upper Limit | °C | Read | |||
| Room Setpoint Lower Limit | °C | Read | |||
| DHW Setpoint Upper Limit | °C | Read | |||
| DHW Setpoint Lower Limit | °C | Read | |||
| DHW Pump Running Time | min | Read | |||
| Parameter Setting 1 | Read | ||||
| Parameter Setting 2 | Read | ||||
| dT5 On | °C | Read | |||
| dT1S5 | °C | Read | |||
| DHW Interval | min | Read | |||
| T4 DHW Max | °C | Read | |||
| T4 DHW Min | °C | Read | |||
| TBH Delay | min | Read | |||
| dT5 TBH Off | °C | Read | |||
| T4 TBH On | °C | Read | |||
| Disinfection Temperature | °C | Read | |||
| Disinfection Max Duration | min | Read | |||
| Disinfection High Temperature Time | min | Read | |||
| Cooling Compressor Interval | min | Read | |||
| dT1SC | °C | Read | |||
| dTSC | °C | Read | |||
| T4 Cooling Max | °C | Read | |||
| T4 Cooling Min | °C | Read | |||
| Heating Compressor Interval | min | Read | |||
| dT1SH | °C | Read | |||
| dTSH | °C | Read | |||
| T4 Heating Max | °C | Read | |||
| T4 Heating Min | °C | Read | |||
| T4 IBH On | °C | Read | |||
| dT1 IBH On | °C | Read | |||
| IBH Delay | min | Read | |||
| T4 AHS On | °C | Read | |||
| dT1 AHS On | °C | Read | |||
| AHS Delay | min | Read | |||
| DHW Heat Pump Max Time | min | Read | |||
| DHW Heat Pump Restrict Time | min | Read | |||
| T4 Auto Cooling Min | °C | Read | |||
| T4 Auto Heating Max | °C | Read | |||
| Holiday Heating Setpoint | °C | Read | |||
| Holiday DHW Setpoint | °C | Read | |||
| Floor Drying Rise Days | d | Read | |||
| Floor Drying Peak Days | d | Read | |||
| Floor Drying Drop Days | d | Read | |||
| Floor Drying Peak Temperature | °C | Read | |||
| First Floor Heating Time | h | Read | |||
| First Floor Heating Setpoint | °C | Read | |||
| Custom Curve Cooling T1Set C1 | °C | Read | |||
| Custom Curve Cooling T1Set C2 | °C | Read | |||
| Custom Curve Cooling T4 C1 | °C | Read | |||
| Custom Curve Cooling T4 C2 | °C | Read | |||
| Custom Curve Heating T1Set H1 | °C | Read | |||
| Custom Curve Heating T1Set H2 | °C | Read | |||
| Custom Curve Heating T4 H1 | °C | Read | |||
| Custom Curve Heating T4 H2 | °C | Read | |||
| Power Input Limitation | Read | ||||
| T4 Fresh Times | Read | ||||
| Pump I Delay | h | Read | |||
| Emission Type | Read |
Loading registers…
Send your device list
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
- Show water outlet and inlet temperature, outdoor temperature and compressor frequency of a Midea heat pump on one ModbusCloud dashboard.
- Get an email when Current Fault is no longer 0 or the water outlet temperature drops below a threshold you set.
- Track water flow, capacity and compressor hours in the 365-day history to check how the heat pump runs over a season.
- Change the hot water or water temperature setpoint remotely from the portal.
- Switch hot water production off during a holiday and on again before the return.
- Check high and low pressure and discharge temperature before a service visit.
Installation
Set the Modbus address with rotary switch S3 on the hydraulic module board; position 0 gives address 16.
Connect H1 (A+) and H2 (B-) of the wired controller to the RS485 port of the ModbusCloud Gateway, with termination at both ends of the bus.
In ModbusCloud, add a Modbus device with the same address at 9600 baud, no parity, 1 stop bit, and import this template.
Check that Water Outlet Temperature and Outdoor Temperature T4 show plausible values.
Things to watch for
The heat pump does not answer. What should I check?
Check the address: switch S3 at position 0 means address 16, not 0. Use 9600 baud, 8 data bits, no parity and 1 stop bit. Swap H1 and H2 if needed and make sure only one Modbus master talks to the wired controller.
Why do some registers return an error?
Registers 123 and 247 to 254 are reserved and return an address error when read. Some values, such as zone 2 or room temperature, only make sense when that zone or sensor is installed.
Water flow or capacity looks 100 times too high. Why?
The unit sends water flow and capacity multiplied by 100. The template divides by 100, so check that the scale in the portal is still 0.01 for these two registers.
How do I switch the heat pump on through Modbus?
Power On Off is a bit field: bit 1 switches zone 1, bit 2 hot water, bit 3 zone 2. Write the whole word, for example 6 for zone 1 and hot water on. Writing registers is off per Gateway until it is enabled on request; write only values you understand.
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