Sonoff TRV-ZBT

Device Information

The TRV-ZBT is the second generation (Gen2) of the Sonoff TRV. We recommand to use it with Zigbee2MQTT.

Valve opening entities

Unlike the first generation (TRVZB), this TRV exposes two valve opening values instead of one:

• heating_valve_position: the valve opening used when the TRV is heating,
• idle_valve_position: the valve opening used when the TRV is idle.

VTherm accepts only one opening degree entity per valve. If you only set heating_valve_position as the opening degree entity, the valve does not always open, even when the heating position is above 0.

Workaround: sync the idle position

If you want to use the self-regulation with direct valve control, you can add the following automation. It keeps idle_valve_position just below heating_valve_position (the idle value must be lower than the heating one). Use heating_valve_position as the opening degree entity in VTherm, and replace the entity IDs with yours.

alias: Sonoff TRV-ZBT - Sync valve positions
description: Keep idle valve position just below heating valve position
triggers:
  - trigger: state
    entity_id: number.my_trv_heating_valve_position
  - trigger: homeassistant
    event: start
conditions:
  - condition: template
    value_template: >
      {{ is_number(states('number.my_trv_heating_valve_position')) }}
  - condition: template
    value_template: >
      {% set heating = states('number.my_trv_heating_valve_position') | float %}
      {% set idle = [0, heating - 1] | max %}
      {{ states('number.my_trv_idle_valve_position') | float(-1) != idle }}
actions:
  - action: number.set_value
    target:
      entity_id: number.my_trv_idle_valve_position
    data:
      value: >
        {% set heating = states('number.my_trv_heating_valve_position') | float %}
        {{ [0, heating - 1] | max }}
mode: restart

Temperature step

The TRV only accepts setpoints by steps of 0.5°C. If VTherm uses a 0.1°C step, the setpoint sent to the TRV is rounded (for example 22.2°C becomes 22°C). In that case, the TRV may stay closed even if VTherm asks to open the valve. That's why the configuration below sets a 0.5°C temperature step.

Source: Support for the new SONOFF TRV Gen2 discussion.

Device 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.
4. Uncheck "Use additional central main configuration" and submit.
5. On the next screen, set 0.5 as the temperature step.

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

You can validate and return to the configuration menu.