Set Sonoff TRV external temperature from external sensor

sonoff_trv_external_temp.yaml

blueprint:
  name: TRV External Temp
  description: >
    Sets the external temperature on a Sonoff TRV and ensures it is configured
    to use the external sensor. Select the TRV as a device — entities are
    resolved automatically.
  domain: automation
  source_url: https://gist.github.com/jamesonuk/83111e89e6a05aa728acad3524494be0
  input:
    trv_device:
      name: TRV Device
      description: The Sonoff TRV device to control
      selector:
        device:
          filter:
            - manufacturer: "SONOFF"
              model_id: "TRVZB"
          entity:
            - domain: number
              device_class: temperature
    temp_sensors:
      name: Temp Sensors
      description: External sensor(s) whose readings are pushed to the TRV
      selector:
        entity:
          multiple: true
          filter:
            domain: sensor
            device_class: temperature

mode: restart

triggers:
  - trigger: state
    entity_id: !input temp_sensors

actions:
  - variables:
      trv_device: !input trv_device

      trv_temp_entity: >
        {% set ns = namespace(result='') %}
        {% for eid in device_entities(trv_device) %}
          {% if eid.split('.')[0] == 'number'
             and state_attr(eid, 'device_class') == 'temperature' %}
            {% set ns.result = eid %}
          {% endif %}
        {% endfor %}
        {{ ns.result }}

      trv_mode_entity: >
        {% set ns = namespace(result='') %}
        {% for eid in device_entities(trv_device) %}
          {% if eid.split('.')[0] == 'select' %}
            {% set opts = state_attr(eid, 'options') %}
            {% if opts and 'internal' in opts and 'external' in opts %}
              {% set ns.result = eid %}
            {% endif %}
          {% endif %}
        {% endfor %}
        {{ ns.result }}

  - if:
      - condition: template
        value_template: >
          {{ trv_mode_entity != ''
             and states(trv_mode_entity) == 'internal' }}
    then:
      - action: select.select_option
        target:
          entity_id: "{{ trv_mode_entity }}"
        data:
          option: "external"

  - if:
      - condition: template
        value_template: >
          {{ trv_temp_entity != ''
             and (trigger.to_state.state | float
                  - states(trv_temp_entity) | float) | abs >= 0.1 }}
    then:
      - action: number.set_value
        target:
          entity_id: "{{ trv_temp_entity }}"
        data:
          value: "{{ trigger.to_state.state }}"