Stiebel Eltron Heating & Cooling

Use cases

• Monitor outside temperature, flow temperatures, and buffer tank status on a live cloud dashboard for your customer.
• Create an alert when a heat pump fault or error state is detected to reduce response time for service calls.
• Adjust room temperature comfort and eco setpoints remotely to match occupancy schedules or seasonal changes.
• Integrate hot water temperature control with PV surplus availability to optimize self-consumption of solar energy.
• Track heating circuit operating modes over time using historical data to verify system efficiency and runtime balance.
• Compare actual buffer temperature against target values to identify control deviations early.

Installation

1. 1Connect the Stiebel Eltron ISG Web gateway to your local network and ensure the Modbus TCP interface is enabled (upgrade firmware or purchase the software update if required).
2. 2Connect your ModbusCloud gateway (MCG or MLP series) to the same local network as the ISG Web device.
3. 3Note the IP address of the ISG Web and confirm it is reachable from the ModbusCloud gateway.
4. 4Import the Stiebel Eltron Heating and Cooling template in the ModbusCloud portal and assign the correct IP address and Modbus TCP port (default 502).
5. 5Verify that register readings such as outside temperature and buffer temperature appear correctly on the ModbusCloud dashboard.
6. 6Test a writable control, such as changing the hot water comfort temperature setpoint, and confirm the change is reflected on the ISG Web display.

Things to watch for

01

Do I need a separate software update for the ISG Web to use Modbus TCP?

Older ISG Web versions require a chargeable software update from Stiebel Eltron to activate the Modbus TCP interface. Newer ISG Web models have this interface built in. Check with your Stiebel Eltron distributor before purchasing.

02

Why are my temperature readings off by one register?

Stiebel Eltron documentation lists register numbers that are offset by 1 from the actual Modbus addresses. Register 519 in the manual corresponds to address 518. The template already accounts for this offset.

03

Which Stiebel Eltron models are supported by this template?

The template is designed for WPM (version 3 and above), WPL, and LPZ series heat pumps connected through the ISG Web gateway. Verify ISG compatibility with your specific model before installation.

04

What data format do the temperature registers use?

Temperature registers use uint16 or int16 format and report values in degrees Celsius. No additional scaling factor is needed for most registers.

Registers (22)

20 read / 7 write

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