Introduction
I bought a new Vaillant ( Hr-ketel ecoTEC plus) central heating boiler a few months back, my old boiler from 2001 still worked, but I rather had it replaced, before it broke. When ordering there was an option to make it connected with the vSMART for about €200 extra. It sounded a bit to much and saw no integration with Home Assistant (HA) directly (at that time). So I tried an alternate way.
eBUS
Vaillant uses a protocol called eBUS for external communication. This protocol is based on UART but at different voltage levels, so be able to use this protocol we need some hardware to do the translation. Although there were some solutions available online, I couldn’t find a tiny and SMD variant. This is why I decided to create my own PCB in KiCAD. My design is based on the following project: https://ebus.github.io/adapter/. My project can be found here: https://gitlab.com/fromeijn/ebuzzz-adapter
This PCB uses a USB to UART converter board with an CP2102, e.g this one. It is electrically isolated so no harmful ground loops or other issues can occur. There are also some helpfull LEDs to show you what is going on.
Home Assistant Integration
To integrate with Home Assistant I used ebusd running on an Raspberry Pi I had laying around. The ebusd has an MQTT client integrated, this is an easy way to hook it up to Home Assistant. I used it in the following configuration for ebusd:
/etc/default/ebusd
EBUSD_OPTS="--scanconfig
--configpath=/home/pi/ebusd-configuration/ebusd-2.1.x/en --mqtthost=<homeassistant_ip> --mqttport=1883 --mqttuser=<user> --mqttpass=<passwd>"In Home Assistant I used the MQTT HVAC integration and set is up as follows:
climate:
- platform: mqtt
name: CV
modes:
- auto
- heat
- cool
- 'off'
mode_state_template: >-
{% set values = { 'auto':'auto', 'on':'heat', 'night':'cool', 'summer':'off'} %}
{{ values[value] if value in values.keys() else 'off' }}
mode_command_topic: "convert/modeset"
mode_state_topic: "ebusd/350/Hc1OPMode"
temperature_state_topic: "ebusd/350/DisplayedHc1RoomTempDesired"
temperature_low_state_topic: "ebusd/350/Hc1NightTemp"
temperature_high_state_topic: "ebusd/350/Hc1DayTemp"
temperature_low_command_topic: "ebusd/350/Hc1NightTemp/set"
temperature_high_command_topic: "ebusd/350/Hc1DayTemp/set"
current_temperature_topic: "ebusd/350/DisplayedRoomTemp"Sadly my Valliant / ebusd doesn’t understand heat, cool. Also my heater can not cool (of course), but it has a night mode (low temperature setting), we use that instead. So we need to translate heat to on and cool to night, we do this with this automation:
- id: 1234
alias: Convert HVAC Mode
trigger:
- platform: mqtt
topic: convert/modeset
action:
- data_template:
payload: '{% set mode_name = trigger.payload %} {% set modes = { ''off'':''summer'',
''heat'':''on'', ''cool'':''night'', ''auto'':''auto'' } %} {{ modes[mode_name]
if mode_name in modes.keys() else ''auto'' }}'
topic: ebusd/350/Hc1OPMode/set
service: mqtt.publish
Conclusion
With this integration we can control the temperature remotely or automatically. I’ve added presence detection and a google calendar so no energy is wasted which is a big plus for me. This project was fun to get my home automation kick stared and I learned something one the way. Hope this helps some of you as well!