z2m_aqara_trv_external_temperature.yaml

z2m_aqara_trv_external_temperature.yaml

blueprint:
  name: Aqara TRV E1 External Temperature Control
  description: >
    This automation allows the Aqara TRV E1 Smart Radiator Thermostat to use temperature readings from an external sensor rather than its internal sensor. Whenever the temperature sensor reports a new value, it is sent to the TRV for more accurate climate control.
  domain: automation
  source_url: "https://gist.github.com/pavax/8d6ed250765d89cb281d4a1762b8d2e8"

  input:
    external_temp_sensor:
      name: External Temperature Sensor
      description: Select the temperature sensor that will provide temperature readings to the Aqara TRV.
      selector:
        entity:
          filter:
            domain: sensor
            device_class:
              - temperature

    aqara_trv_device:
      name: Aqara TRV Device
      description: Select the Aqara Smart Radiator Thermostat E1 that will receive the external temperature data.
      selector:
        device:
          multiple: false
          filter:
            - integration: mqtt
              manufacturer: Aqara
              model: Smart radiator thermostat E1 (SRTS-A01)
            - integration: mqtt
              manufacturer: Aqara
              model: Smart radiator thermostat E1
            - integration: mqtt
              manufacturer: Aqara
              model: Aqara Smart Radiator thermostat E1 (SRTS-A01)
            - integration: mqtt
              manufacturer: Aqara
              model: Aqara smart radiator thermostat E1 (SRTS-A01)

    external_temperature_input_name:
      name: TRV's Input Sensor Name
      description: Enter a keyword or name used to identify the TRV’s number sensor entity-id, which sets the external temperature value. Defaults to 'external'.
      selector:
        text:
      default: "external"

mode: single
max_exceeded: silent

variables:
  aqara_trv_device: !input aqara_trv_device
  external_temp_sensor: !input external_temp_sensor
  external_temperature_input_name: !input external_temperature_input_name

trigger:
  - trigger: state
    entity_id: !input external_temp_sensor

action:
  - variables:
      aqara_trv_device_name: "{{ device_attr(aqara_trv_device, 'name') }}"
      aqara_trv_select_entity: >-
        {% set device_entities = device_entities(aqara_trv_device) %}
        {{ expand(states['select'])   
                  | selectattr('entity_id','in', device_entities)
                  | selectattr('attributes.options', 'contains', 'external')
                  | map(attribute='entity_id') 
                  | first
        }}
      aqara_trv_number_entity: >-
        {% set device_entities = device_entities(aqara_trv_device) %}
        {{ expand(states['number'])   
                  | selectattr('entity_id','in', device_entities)
                  | selectattr('entity_id', 'contains', external_temperature_input_name)
                  | map(attribute='entity_id') 
                  | first
        }}

  - if:
      - condition: template
        value_template: >-
          {{ is_state(external_temp_sensor, "unavailable") or is_state(external_temp_sensor, "unknown") }}
    then:
      - action: select.select_option
        target:
          entity_id: "{{aqara_trv_select_entity}}"
        data:
          option: internal
      - action: system_log.write
        data:
          level: error
          message: External temperature sensor unavailable
          logger: Aqara TRV
      - stop: External temperature sensor unavailable

  - if:
      - condition: template
        value_template: "{{ not is_state(aqara_trv_select_entity, 'external')}}"
    then:
      - action: select.select_option
        target:
          entity_id: "{{aqara_trv_select_entity}}"
        data:
          option: external
      - delay:
          hours: 0
          minutes: 0
          seconds: 10
          milliseconds: 0

  - action: number.set_value
    data:
      value: >-
        {{ (states(external_temp_sensor)|float(0)|round(1)) }}
    target:
      entity_id: "{{aqara_trv_number_entity}}"

I'd like to point out a fatal flaw with this blueprint, especially for people living in countries where heating is seriously expensive:
What happens if the external temperature sensor fails, and its state becomes unavailable or unknown?

In my observation, unavailable or unknown turns into 0 when cast/converted to float using {{ (states(external_temp_sensor)|float(0)|round(1)) }}.
The TRV receives that 0 value, thinks its super cold and opens the valve to 100%, and it stays that way until fixed manually. That actually happened to me while I was out on vacation. That did hurt in my wallet.

Here's a way to fix it. By falling back to the TRV's internal sensor when the external one fails.

actions:
  - variables:
    # ...
  - if:
      - condition: template
        value_template: >-
          {{ is_state(external_temp_sensor, "unavailable") or is_state(external_temp_sensor, "unknown") }}
    then:
      - action: select.select_option
        target:
          entity_id: "{{aqara_trv_select_entity}}"
        data:
          option: internal
      - stop: Temperature sensor failed.
    # ...

I'd like to point out a fatal flaw with this blueprint, especially for people living in countries where heating is seriously expensive: What happens if the external temperature sensor fails, and its state becomes unavailable or unknown?

In my observation, unavailable or unknown turns into 0 when cast/converted to float using {{ (states(external_temp_sensor)|float(0)|round(1)) }}. The TRV receives that 0 value, thinks its super cold and opens the valve to 100%, and it stays that way until fixed manually. That actually happened to me while I was out on vacation. That did hurt in my wallet.

Here's a way to fix it. By falling back to the TRV's internal sensor when the external one fails.

actions:
  - variables:
    # ...
  - if:
      - condition: template
        value_template: >-
          {{ is_state(external_temp_sensor, "unavailable") or is_state(external_temp_sensor, "unknown") }}
    then:
      - action: select.select_option
        target:
          entity_id: "{{aqara_trv_select_entity}}"
        data:
          option: internal
      - stop: Temperature sensor failed.
    # ...

Thanks for pointing out this flaw- I updated the script.