Bösch x-change
The Bösch x-change is an air-to-water heat pump controlled by the x-center pro controller, used for residential and light-commercial heating in Austria and the wider EU. This ModbusCloud template connects via Modbus TCP to the x-center pro and reads current power consumption and two temperature registers: the measured temperature and the active temperature limit. It also exposes the PV modulation power setpoint register, which lets energy management systems direct surplus solar power into the heat pump. Monitoring these four registers gives installers direct visibility into heat pump loading and thermal state from the ModbusCloud portal.
- Protocol
- Modbus TCP
- Connection
- Ethernet, Modbus TCP
- Registers
- 4, read and write
- Brand
- Bösch
- Compatible models
- x-change · x-center pro
- Last updated
Registers (4)
3 read, 1 write
| Name | Unit | Access | Address (Hidden until you enter your email) | Function (hidden) | Type (hidden) |
|---|---|---|---|---|---|
| setmaxpower | W | Write | |||
| power | W | Read | |||
| temp | °C | Read | |||
| limittemp | °C | 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
- Monitor current power consumption of the Bösch x-change to verify operation against expected load profiles.
- Track the measured temperature register over time to detect sensor drift or unexpected heating cycle behaviour.
- Alert on deviations between the reported temperature and the active temperature limit to catch control faults early.
- Write the PV modulation setpoint to direct surplus solar energy into the heat pump during peak generation hours.
- Compare power readings across multiple Bösch x-change installations in your portal to benchmark site performance.
Installation
Contact Bösch or Kermi support to have Modbus TCP activated on the x-center pro controller; this cannot be enabled by the user and requires the interface module to be on firmware version v1.6.1.80 or higher.
Connect the x-center pro to your local network via its Ethernet port and confirm the device is reachable on the LAN at port 502 before proceeding.
In the ModbusCloud portal, add the ModbusCloud Gateway, import the Bösch x-change template, and set the Modbus unit ID to 40, which is the default device ID for the x-center pro.
Verify the connection by reading register 108 (power) in the portal's live register view and confirming the value matches the reading shown on the x-center pro display.
Things to watch for
Modbus TCP is enabled but the gateway cannot reach the x-center pro. Why?
Modbus TCP must be explicitly activated by Bösch or Kermi service; the setting is not accessible in user or expert mode on the controller. Confirm with support that activation is complete and that the interface module firmware is at v1.6.1.80 or higher. Also verify the x-center pro and the ModbusCloud Gateway are on the same network segment and that port 502 is not blocked by a firewall.
The gateway connects but register reads return errors or drop out intermittently.
The x-center pro requires a polling interval of more than 2000 milliseconds between requests. If the ModbusCloud Gateway polls faster than this, the controller can stop responding and may require a reboot. Set the template polling interval to at least 3000 milliseconds to avoid overloading the controller's Modbus stack.
Temperature register values look offset or implausible. What could cause this?
The temp and limittemp registers return int16 values with no unit scaling in the template. Check whether the x-center pro applies a factor of 0.1 (tenths of a degree) in your specific firmware version. Cross-check the raw register value against the display on the controller before assuming sensor failure. Community reports also note some signed/unsigned ambiguity in older firmware; confirm int16 interpretation is correct.
Is it safe to write to the setmaxpower register at any time?
Writing to the setmaxpower register (address 301) directly commands the PV modulation power target on the heat pump. Sending values outside the range the controller expects, or writing repeatedly in rapid succession, can trigger protective limits or put the controller into an unexpected state. Always verify the acceptable range with Bösch or Kermi service documentation before automating writes, and include a watchdog in your control logic to reset the setpoint if the managing system goes offline.
Want to see how it works?
