This custom Home Assistant integration monitors a WTH UMR2 heating regulator over the local network. It is not affiliated with WTH and currently provides read-only sensor entities; it does not send commands to the regulator.
This project is based on the original WTH UMR2 Home Assistant project, released under the MIT License. It has been substantially revised for the controller's local JSON API and current Home Assistant integration behavior.
- Home Assistant 2025.1.0 or newer
- A WTH UMR2 reachable from the Home Assistant host
- The regulator's IP address or resolvable hostname
The integration uses plain HTTP and has no external Python requirements.
Add this repository as a custom repository in HACS, choose Integration, and install WTH UMR2 Regulator. Restart Home Assistant afterwards.
Copy custom_components/wth_umr2 into the
custom_components directory of the Home Assistant configuration directory,
then restart Home Assistant.
Remove the WTH UMR2 integration from Settings > Devices & services. Select the configured WTH UMR2 device, open the menu, and choose Delete. Restart Home Assistant if the integration was installed manually.
- Open Settings > Devices & services.
- Select Add integration and search for WTH UMR2 Regulator.
- Enter the regulator's IP address or hostname.
- Submit the form.
The config flow validates the device before creating the entry and prevents the same host from being configured more than once.
One device is created for each configured regulator. The integration polls the status sections separately every 30 seconds to stay within the controller's JSON response limit. Communication subsections are requested individually because their device arrays can be large:
http://<host>/get.json?f=$.status.version.*
http://<host>/get.json?f=$.status.main.*
http://<host>/get.json?f=$.status.inputs.*
http://<host>/get.json?f=$.status.process.*
http://<host>/get.json?f=$.status.outputs.*
http://<host>/get.json?f=$.status.communications.fanlink.*
http://<host>/get.json?f=$.status.communications.rf.*
http://<host>/get.json?f=$.status.communications.modbus.*
http://<host>/get.json?f=$.status.communications.bluetooth.*
http://<host>/get.json?f=$.status.communications.ethernet.*
http://<host>/get.json?f=$.status.communications.json.*
http://<host>/get.json?f=$.status.communications.usb.*
The responses are merged and used to create 114 sensors:
- Main state, operating mode, display, LED status, and heat/cool/PWM factors
- Heater, cooler, and pump output percentages
- Eight thermostat states and eight thermostat temperatures
- Ten valve positions
- Maximum, return, and condensate inputs
- Ten temperature inputs
- Power-stealing input status
- Fanlink, RF, Modbus, Bluetooth, JSON, USB, and Ethernet status
- Ten thermostat demand factors
- Ten devices each for Fanlink, RF, Modbus, and Bluetooth diagnostics
- PID tuning and output-factor diagnostics
- Firmware build and controller API version diagnostics
Temperature entities are created during setup, but each one is enabled by default only when its first successful update reports a positive temperature. This keeps inactive inputs out of the default entity list while supporting UMR2 installations that provide temperature data. Disabled entities can be enabled manually from the device's entity settings.
Communication and connected-device entities are marked as diagnostic. Entity availability follows the coordinator's last successful update.
The regulator must return HTTP 200 from each endpoint with a JSON object
containing a status object and the requested section. HTTP errors, timeouts,
connection failures, invalid JSON, and incomplete responses are reported as
update failures. The integration does not provide authentication, TLS, writes,
or service actions.
- Confirm the host is reachable from the machine running Home Assistant.
- Check Settings > System > Logs for
wth_umr2errors. - Confirm each status endpoint returns JSON with a top-level
statuskey. - If the device was previously configured, remove the existing config entry before attempting to add the same host again.
This project is being cleaned up and reworked. The current implementation is small and intentionally documents only behavior present in the code.
MIT License. See LICENSE.