Kermi x-center pro
The Kermi x-center pro is a wall-mounted heat pump controller that manages the Kermi x-change heat pump, providing heating, cooling, and domestic hot water control via a 7-inch touchscreen. This ModbusCloud template connects over Modbus TCP and reads current power consumption, measured temperature, and the active temperature limit. It also exposes the PV surplus power setpoint register, enabling solar self-consumption control. Monitoring these values in your portal gives installers and building managers a clear view of heat pump operating state without manual on-site checks.
- Protocol
- Modbus TCP
- Connection
- Ethernet, Modbus TCP
- Registers
- 4, read and write
- Brand
- Kermi
- 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 to verify the heat pump operates within expected load ranges.
- Track the measured temperature register to detect sensor drift or unexpected operating conditions over time.
- Alert on temperature limit register changes to catch controller reconfiguration events quickly.
- Write PV surplus power values to the setmaxpower register to steer the x-change compressor using solar generation.
- Compare measured temperature and power readings across multiple sites in the ModbusCloud multi-site overview.
Installation
Contact Kermi support by email to have Modbus TCP activated on your x-center pro controller remotely, as the protocol cannot be enabled from the local user or technician menu.
Connect the x-center pro to your local LAN via its RJ45 Ethernet port and confirm it receives a static or reserved IP address on the same network segment as the ModbusCloud Gateway.
In the ModbusCloud portal, add a new Gateway, create a new device using the Kermi x-center pro template, set the IP address and port 502, and use Modbus unit ID 40 as the default for Kermi devices.
Verify the connection by checking that registers 100, 101, and 108 return live values in the portal register view; reboot the x-center pro if the controller stops responding after the first poll.
Things to watch for
Modbus TCP port 502 is not reachable on the x-center pro. Why?
Modbus TCP on the x-center pro must be activated remotely by Kermi support. The setting is not accessible in the local user or expert menu. Contact Kermi service and request Modbus TCP activation for your unit. The controller must be reachable via the internet for their team to apply the change.
The gateway connects but all register values show zero or errors.
Verify that unit ID 40 is used, as this is the default Modbus device ID for Kermi x-center controllers. Also ensure the poll interval is set to at least 2000 milliseconds. Polling faster than this can cause the x-center pro to stop responding and may require a controller reboot to recover.
Temperature and power values look implausible or scaled oddly. What is wrong?
The x-center pro reports int16 values without a declared unit in some firmware versions. Temperature registers may use a scaling factor of 0.1 or 1 depending on controller firmware. Cross-check against the display reading on the controller itself. If values are off by a factor of 10, apply a scaling divisor of 10 in your portal channel configuration.
Is it safe to write values to the setmaxpower register regularly?
Use the setmaxpower register (address 301) with care. Writing excessively high power values or updating it faster than every few minutes can interfere with the x-change compressor control logic. Always verify that the written value corresponds to actual measured PV surplus. Incorrect setpoints can cause unnecessary compressor cycling and may affect warranty conditions.
More Kermi templates
Want to see how it works?
