# Eurotronic Comet

The Eurotronic Comet Zigbee TRVs (COZB0001, CoZB_dha) can be used with [self-regulation by direct valve control](https://www.versatile-thermostat.org/en/docs/self-regulation/#self-regulation-by-direct-valve-control).

## Zigbee2MQTT settings

Set `trv_mode` to `1` in Zigbee2MQTT. In this mode, the valve is controlled directly with `valve_position`: the display shows the valve opening and the buttons of the TRV are disabled. With the default value `2`, the TRV regulates on its own and ignores `valve_position`.

The TRV can switch back to automatic mode on its own: check `trv_mode` if the valve stops following _VTherm_.

## Maximum opening

`valve_position` ranges from 0 (closed) to 255 (fully open), not from 0 to 100. Set the maximum opening (`max_opening_degrees`) to `255` so that _VTherm_ uses the full range of the valve. With a maximum of 100, the valve would never open more than about 40 %.

## Compatibility status

- **Community**: This device has been reported as fully functional by the community. Devices: Eurotronic - COZB0001, Eurotronic Comet

## VTherm configuration

### Initialization

Go to your settings, then integrations, then click on add a new integration. Search for Versatile Thermostat.

Click on Thermostat over another thermostat.

### Basic attributes

Go to the "Main attributes" section.

1. Choose a name for your thermostat
2. Set the temperature sensor for your room
3. If you are using the Zigbee protocol and you have a "last_seen" entity for your temperature sensor, fill it in.

You can validate and return to the configuration menu.

### Underlying entities

Go to the underlying entities section.

1. Add the thermostats that will be controlled
2. In the auto-regulation section, choose "direct valve control"

You can validate and return to the configuration menu.

## Community references

Additional references may be old. A bug reported on an old version of VTherm may have been corrected on a more recent version.

- [#1660 Max open valve is limited to 100, but Eurotronics Comet uses 255 steps for valve opening degree](https://github.com/jmcollin78/versatile_thermostat/issues/1660)
- [#1734 Comet Zigbee TRV automatically switches to "Auto" mode](https://github.com/jmcollin78/versatile_thermostat/issues/1734)