Lambda Heating & Cooling
Controls Lambda air-water heat pumps for heating and cooling via Modbus TCP or RTU.
This template connects Lambda air-water heat pumps to ModbusCloud via Modbus TCP or RTU. It reads buffer temperatures, hot water storage data, COP, and power consumption. It also provides control over hot water target temperature, supply flow setpoints, and operating modes for two heating circuits.
- Protocol
- Modbus TCP
- Connection
- Ethernet, Modbus TCP
- Registers
- 32, read and write
- Brand
- Lambda
- Key readings
- Heat/Cool buffer temperatures (top/bottom) · Hot water storage temperatures (top/bottom) · Heatpump power consumption and COP · Supply and return flow temperatures · Heatpump inverter thermal/electrical power · Average outside temperature
- Available commands
- Hot water target temperature · Target supply flow temperature HC1/HC2 · Target operating mode HC1/HC2 · Input power E-Manager
- Compatible models
- EU08L · EU13L · EU15L · EU20L · Zewotherm <Lambda> EU08L · Zewotherm <Lambda> EU13L · Zewotherm <Lambda> EU15L · Zewotherm <Lambda> EU20L
- Last updated
Registers (32)
27 read, 8 write
| Name | Unit | Access | Address (Hidden until you enter your email) | Function (hidden) | Type (hidden) |
|---|---|---|---|---|---|
| 3001 State Operating Mode Heat/Cool Buffer | Read | ||||
| 3002 Actual Heat/Cool Buffertemperature Top | °C | Read | |||
| 3003 Actual Heat/Cool Buffertemperature Bottom | °C | Read | |||
| 2001 State Operating Mode Hot Water Storage | Read | ||||
| 2002 Actual Hot Water Storage Temperature Top | °C | Read | |||
| 2003 Actual Hot Water Storage Temperature Bottom | °C | Read | |||
| 5001 State Operating Mode HC1 | Read | ||||
| 5002 Actual Supply Flowtemperature HC1 | °C | Read | |||
| 0103 Actual Heatpump Power Consumption | kW | Read | |||
| 0003 Actual Outsidetemperature average | °C | Read | |||
| 1000 State Heatpump Error | Read | ||||
| 1002 State Heatpump Operation State | Read | ||||
| 1003 State Heatpump Operation Mode | Read | ||||
| 1004 Actual Heatpump Supply Flowtemperature | °C | Read | |||
| 1005 Actual Heatpump Return Flowtemperature | °C | Read | |||
| 1006 Actual Heatpump Flow Rate | l/min | Read | |||
| 1007 Actual Heatpump Outdoorsuctiontemperature | °C | Read | |||
| 1011 Actual Heatpump Inverter Thermal Power | kW | Read | |||
| 1012 Actual Heatpump Inverter Electrical Power | kW | Read | |||
| 1013 Actual Heatpump COP | Read | ||||
| 1001 State Heatpump Error number | Read | ||||
| 2050 State Hot Water Targettemperature | °C | Read and write | |||
| 1019 State Relais Request Contact additional heat generator | Read | ||||
| 5102 Actual Supply Flowtemperature HC2 | °C | Read | |||
| 5101 State Operating Mode HC2 | °C | Read | |||
| 5050 State Offset Flow Line Temperature HC1 | °C | Read and write | |||
| 5150 State Offset Flow Line Temperature HC2 | °C | Read and write | |||
| 5005 Target Supplyflowtemperature HC1 | °C | Write | |||
| 0102 Actual Input Power-General E-Manager | kW | Write | |||
| 5006 Target Operating Mode HC1 | Write | ||||
| 5105 Target Supplyflowtemperature HC2 | °C | Write | |||
| 5106 Target Operating Mode HC2 | 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 buffer and hot water storage temperatures on a live cloud dashboard for your customer.
- Create an alert when the COP drops below a defined threshold to detect efficiency problems early.
- Adjust hot water target temperature remotely to align heat pump operation with PV surplus or flexible tariffs.
- Track power consumption and thermal output over time to generate monthly performance reports.
- Switch heating circuit operating modes based on seasonal schedules or occupancy patterns.
- Integrate E-Manager input power control to coordinate the heat pump with on-site energy management.
Installation
Activate Modbus TCP or RTU on the Lambda heat pump following the instructions in the Lambda Helpcenter download area.
Connect the ModbusCloud Gateway to the heat pump via Ethernet for Modbus TCP, or via RS-485 wiring (A, B, GND) for Modbus RTU.
Set the correct Modbus slave address on the heat pump to match the address configured in the template.
For Modbus RTU connections, verify that the baud rate, parity, and stop bits on the gateway match the heat pump settings.
Import the Lambda Heating & Cooling template in the ModbusCloud portal and assign it to the connected gateway.
Verify that live readings such as buffer temperatures and power consumption appear on the ModbusCloud dashboard.
Things to watch for
I cannot read any registers after connecting via Modbus TCP. What should I check?
Modbus TCP must be explicitly activated on the Lambda heat pump. Check the Lambda Helpcenter for the activation procedure. Also verify that the gateway and heat pump are on the same network subnet and that the correct IP address is configured in ModbusCloud.
What data types and scaling do the temperature registers use?
Most temperature and power registers use int16 with values in degrees Celsius or kW. Flow line temperature offset registers 5050 and 5150 are uint16. The template already includes the correct data type and scaling, so no manual adjustments are required.
Which Lambda models are supported by this template?
The template supports EU08L, EU13L, EU15L, and EU20L. Zewotherm branded versions of the same models (Zewotherm EU08L through EU20L) are also compatible, as the Modbus register map is identical.
Can I use Modbus RTU and Modbus TCP at the same time?
Refer to the Lambda documentation for details on simultaneous protocol support. In most cases, the heat pump supports one active Modbus connection at a time. Choose the protocol that matches your ModbusCloud gateway hardware.
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