ASKOMA Askoheat+
Converts surplus renewable electricity into stored heat via Modbus TCP control.
This ModbusCloud template controls the ASKOHEAT+ electric heater from ASKOMA AG over Modbus TCP. The device converts surplus renewable electricity from PV, wind, or CHP into thermal energy stored in a buffer tank. The template reads temperature, actual load, emergency mode, and actual temperature limit, and writes power step, load setpoint, and load feed-in values.
- Protocol
- Modbus TCP
- Connection
- Ethernet, Modbus TCP
- Registers
- 7, read and write
- Brand
- ASKOMA AG
- Key readings
- Temperature · Emergency Mode · Actual Load · Actual Temperature Limit
- Available commands
- Power Step · Load Setpoint · Load Feedin
- Compatible models
- ASKOHEAT+
- Last updated
Registers (7)
4 read, 3 write
| Name | Unit | Access | Address (Hidden until you enter your email) | Function (hidden) | Type (hidden) |
|---|---|---|---|---|---|
| Temperatur | °C | Read | |||
| Emergency Mode | Read | ||||
| Actual Load | W | Read | |||
| Actual Temperatur Limit | °C | Read | |||
| Power Step | Write | ||||
| Load Setpoint | Write | ||||
| Load Feedin | 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
- Divert surplus PV production to hot water instead of exporting at low feed-in tariff rates.
- Build a ModbusCloud automation that reads a grid meter and writes Load Setpoint to the ASKOHEAT+ every few seconds for tight PV self-consumption.
- Log actual load over the day to quantify how much PV surplus was captured as heat.
- Alert the installer when emergency mode triggers, which usually means the buffer tank reached its temperature limit.
- Compare pre and post ASKOHEAT+ installation savings by tracking export reduction over time.
Installation
Enable Modbus TCP on the ASKOHEAT+ controller via the device configuration interface.
Connect the ASKOHEAT+ to the local LAN and note its IP address.
In ModbusCloud, add a Modbus TCP device at the ASKOHEAT+ IP, port 502, slave ID 1.
Import the ASKOMA Askoheat+ template. Readings appear immediately.
To use the internal autoregulator, write Load Feedin every few seconds from a ModbusCloud automation that polls your grid meter.
Things to watch for
Which do I use: Load Setpoint or Load Feedin?
Load Setpoint is the direct power target (you tell the ASKOHEAT+ how many watts to absorb). Load Feedin is the surplus power from the grid meter (you tell the ASKOHEAT+ how much PV is currently being exported). Pick one control strategy and stick with it.
Temperature at 325 reads strangely. Byte order?
Register 325 is float32 spanning two Modbus addresses. If the value is clearly wrong, try toggling the byte order in ModbusCloud device settings. The default is ABCD but some firmware revisions use CDAB.
Want to see how it works?
