@grantmethestrength thanks! Just had a play around and created a new dashboard as suggested. Work in progress...

@mphb the only controls I'm struggling to locate on HA are zone 1 heating on/off, and holiday mode. Have you had any joy finding these switches at all? 

edit- just found the zone 1 heating on/off control. Looks like holiday away isn't controllable via the svenar device as it is just listed as a sensor.

@benson

 
Just had a quick look at the source code for the svenar and these might get you on the right track. In Home Assistant go to settings, devices and services and then entities and search for enable heating and holiday.

Another handy tip always give your entities an area and a label makes it easier to find them when you start to add more stuff in HA.

After a bit more fiddling around (with thanks for pointers with home assistant- very much appreciated), here's what I have. Firstly, the svenar unit itself which was easy enough to connect up:

HA dashboard configuration thus far:

As mentioned above the only slight annoyance is lack of control of holiday away, from what I can see. Otherwise, seems a very tidy device which seems to provide everything I need, I think (?) and utilises the already good functionality in HA both on desktop and in the app. Only slight downside of HA is that it cannot be accessed away from the network without a subscription to the home assistant cloud, or another workaround. Plenty of guides on how to do that, though. 

@benson I use tailscale very easy to setup and rock solid.

@grantmethestrength thanks! I did use that entity search function a lot when sorting which ones I wanted, albeit the midea nomenclature is rather confusing. I think that "enable heating" one basically means actual heating mode on the ASHP rather than turning the central heating on. Not quite sure what the holiday home setting does but it is the away one I need and that only appears to be listed as a sensor. I might email him and ask.

Posted by: @grantmethestrength

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@benson I use tailscale very easy to setup and rock solid.

Tailscale is kind of like a vpn connection (on steroids) you down load it onto each device you want in your tailnet load the integration into home assistant and you now have secure access to your network and home assistant from anywhere in the world. And as a Yorkshireman the best thing is it is free!

https://tailscale.com

I think I may have found it, it looks like it is holding register 5 bit number 5, which means you should be able to read and write to it but it is only in there as a binary sensor not a switch. If you replace the switch portion of heatpump.yaml this should give you the switch. Obvs back up before changing lol!!

switch:
  - platform: factory_reset
    name: Restart with Factory Default Settings
  # Register: 0 -> Bit 2
  - platform: modbus_controller
    modbus_controller_id: "${devicename}"
    name: "${entity_prefix} Power DHW T5S"
    id: "${devicename}_power_dhw_t5s"
    register_type: holding
    entity_category: config
    address: 0x0
    bitmask: 0x4
  - platform: modbus_controller
    modbus_controller_id: "${devicename}"
    name: "${entity_prefix} Function Setting Holiday Away"
    id: "${devicename}_function_setting_holiday_away_switch"
    register_type: holding
    address: 0x5
    bitmask: 0x20  # Bit 5
    icon: mdi:airplane
  # Register: 5 -> Bit 12
  - platform: modbus_controller
    modbus_controller_id: "${devicename}"
    name: "${entity_prefix} Weather Compensation Zone 1"
    id: "${devicename}_weather_compensation_zone_1"
    register_type: holding
    entity_category: config
    address: 0x5
    bitmask: 0x1000
  # Register: 5 -> Bit 13
  - platform: modbus_controller
    modbus_controller_id: "${devicename}"
    name: "${entity_prefix} Weather Compensation Zone 2"
    id: "${devicename}_weather_compensation_zone_2"
    register_type: holding
    entity_category: config
    address: 0x5
    bitmask: 0x2000

  # Register: 7
  - platform: modbus_controller
    modbus_controller_id: "${devicename}"
    name: "${entity_prefix} Forced Water Tank Heating On/Off"
    id: "${devicename}_forced_water_tank_heating_on_off"
    icon: mdi:fire-alert
    address: 0x7
    register_type: holding
    entity_category: config
    write_lambda: |-
      uint16_t value = 0;

      if (x == 1) {
        ESP_LOGI("main", "Set forced water tank heating ON");
        value = 1;
      } else {
        ESP_LOGI("main", "Set forced water tank heating OFF");
        value = 2;
      }

      esphome::modbus_controller::ModbusCommandItem set_payload_command = esphome::modbus_controller::ModbusCommandItem::create_write_single_command(${devicename}, 0x7, value);
      ${devicename}->queue_command(set_payload_command);

      return {};

If there any more sensors that are holding registers that you would like to have a switch for let me know, it is pretty easy to create. Might be worth reaching out to the creator and see if he will update the yaml. It is a cool little family project.