How to configure a MVHR system?

Configuration
1

Okay, so here’s my challenge:

I have in my home a MVHR (Mechanical Ventilation with Heat Recovery System) system that has 3 speed settings: low, medium and high. The speeds on the device itself are controlled by a 2 channel WiFi relay I installed.

When channel 1 is off the speed is ‘Low’
When channel 1 is on and channel 2 is off the speed is ‘Medium’
and when both channels are on the speed is ‘High’

Now, I would like to do 2 things in HA:

  • To display a single drop down in the UI that lets me select the speed (low, medium, high), and also updates automatically when the relay switches are toggled from somewhere else
  • To automate setting the speed based on some triggers (button pressed, humidity sensor, etc.)

I achieved the first by using the rather obscure ‘select’ template as follows in my configuration.yaml:

template:
  - select:
      - name: "WtW Ventilatie Stand"
        unique_id: wtw_ventilatie_stand
        icon: mdi:fan
        state: >
          {%
          set map = {
          is_state('switch.relais_wtw_zolder1','off'): 'Laag',
          is_state('switch.relais_wtw_zolder1','on') and is_state('switch.relais_wtw_zolder2','off'): 'Middel',
          is_state('switch.relais_wtw_zolder1','on') and is_state('switch.relais_wtw_zolder2','on'): 'Hoog',
          } %}
          {{ map.get(True) }}
        select_option:
          - choose:
              - conditions: "{{ option == 'Laag' }}"
                sequence:
                  - service: switch.turn_off
                    target:
                      entity_id:
                        - switch.relais_wtw_zolder1
                        - switch.relais_wtw_zolder2
              - conditions: "{{ option == 'Middel' }}"
                sequence:
                  - service: switch.turn_on
                    target:
                      entity_id: switch.relais_wtw_zolder1
                  - service: switch.turn_off
                    target:
                      entity_id: switch.relais_wtw_zolder2
              - conditions: "{{ option == 'Hoog' }}"
                sequence:
                  - service: switch.turn_on
                    target:
                      entity_id:
                        - switch.relais_wtw_zolder1
                        - switch.relais_wtw_zolder2
        options: "{{ ['Laag', 'Middel', 'Hoog'] }}"

(note: the speeds are in Dutch; ‘Laag’ means low, ‘Middel’ means medium and ‘Hoog’ means high)

I’m not entirely sure this the right approach; I can get the drop down in the UI using the following card yaml:

type: entities
entities:
  - entity: select.wtw_ventilatie_stand
title: Ventilatiestand

And it works exacly like I would expect.

But I’m at a loss on how to use it in an automation; that would require a method to set the state of my select.wtw_ventilatie_stand entity from that automation, and I can’t find any way to do that.

So, am I doing this wrong? Any tips would be greatly appreciated.

2

Anyone? I haven’t found a better way to do this in the mean time. Any help would be appreciated.

4

Hi @BaBaBaBa did you ever manage to make further progress with this? I have a similar query at https://community.home-assistant.io/t/heat-recovery-mvhr-integration-titon-beam-in-ireland-mechanical-ventilation-with-heat-recovery/454942.
Thanks

5

Use this:

action:
  - service: input_select.select_option
    target:
      entity_id: select.wtw_ventilatie_stand
    data:
      option: xy
6

Do you have an Airsmart Ictus MVHR unit by any chance? I am looking to achieve a similar thing; I just had one installed this week and your configuration (relay, 3 speeds) sounds similar to how mine can be configured.