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. To give you an idea how it is hooked up see this drawing below.
To install ebusd on Raspberry Pi OS (Raspbian) you use the following documentation from the ebusd repository: https://github.com/john30/ebusd/wiki/1.-Build-and-install
I used it in the following configuration for ebusd, there are some optional parts.
# add custom config for the VRT350 thermostat (only needed if you have VRT350)
cd /home/pi/
git clone https://github.com/john30/ebusd-configuration.git
cd ebusd-configuration/
cp ebusd-2.1.x/en/vaillant/15.370.csv ebusd-2.1.x/en/vaillant/15.350.csv
# you can change the r; at the beginning of the lines by r1; so it will be read out automatically and pushed on MQTT. If you can also poll values via MQTT, see down below for an example.Edit /etc/default/ebusd
# Without local ebusd-configuration
EBUSD_OPTS="--scanconfig
--mqtthost=<homeassistant_ip> --mqttport=1883 --mqttuser=<user> --mqttpass=<passwd>"
# With local ebusd-configuration
EBUSD_OPTS="--scanconfig
--configpath=/home/pi/ebusd-configuration/ebusd-2.1.x/en --mqtthost=<homeassistant_ip> --mqttport=1883 --mqttuser=<user> --mqttpass=<passwd>"To restart the ebusd
sudo service ebusd restartIn Home Assistant you need to have a MQTT broker setup. In my case I use Mosquitto broker addon, what can be install via the Supervisor. See the documentation of the addon. Also don not forget to add the MQTT integration into your config. I used the MQTT HVAC integration and set is up as follows:
climate:
- platform: mqtt
name: CV
max_temp: 25
min_temp: 15
precision: 0.1
temp_step: 0.5
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_state_topic: "ebusd/350/Hc1OPMode"
mode_command_template: >-
{% set values = { 'auto':'auto', 'heat':'on', 'cool':'night', 'off':'summer'} %}
{{ values[value] if value in values.keys() else 'auto' }}
mode_command_topic: "ebusd/350/Hc1OPMode/set"
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"
Tip: Use MQTT Explorer if you are having problems getting MQTT to work between HA and ebusd.
Automations
When having home assistant and ebusd connected we can start automating things and let the computer do stuff for us. I have configured a google calendar in which I can plan my normal heating schedule. But this only is enabled when i’m home, and turns off when I leave the house.
Heater on/off on calendar
alias: Heater on/off on calendar
description: ''
trigger:
- entity_id: calendar.heater
platform: state
- entity_id: binary_sensor.people_home
platform: state
to: 'on'
condition:
- condition: state
entity_id: binary_sensor.people_home
state: 'on'
- condition: template
value_template: '{{ not is_state("climate.heater", "off") }}'
action:
- choose:
- conditions:
- condition: state
entity_id: calendar.heater
state: 'on'
sequence:
- service: climate.set_hvac_mode
data:
hvac_mode: heat
entity_id: climate.heater
default:
- service: climate.set_hvac_mode
data:
hvac_mode: cool
entity_id: climate.heater
mode: singleHeater low when nobody home
alias: Heater low when nobody home
description: ''
trigger:
- entity_id: binary_sensor.people_home
from: 'on'
platform: state
to: 'off'
for: '00:05:00'
condition: []
action:
- data:
hvac_mode: cool
entity_id: climate.heater
service: climate.set_hvac_mode
mode: singlePoll WaterPressure from bai over ebus
alias: Poll WaterPressure from bai over ebus
description: ''
trigger:
- platform: time_pattern
minutes: /1
condition: []
action:
- service: mqtt.publish
data:
topic: ebusd/bai/WaterPressure/get
mode: single
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!
Board available
Because of lots of requests, the boards are now available on Tindie
Unfortunately currently out of stock, due to chip shortage I’m having trouble producing boards, so I don’t have any time frame for a new batch.
