Many thanks for the add-on and community support. Now I can observe my old heating system.
Did someome also control the waterheating? This would be helpful for a holyday mode.

mqtt:
climate:
object_id: Vailant01
name: Vailant
max_temp: 25
min_temp: 15
precision: 0.1
temp_step: 0.5
action_topic: "ebusd/700/OpMode"
action_template: "{{ value_json.opmode.value }}"
modes:
- auto
- heat
- cool
- "off"
mode_state_template: >-
{% set mode_values = { 'auto':'auto', 'day':'heat', 'night':'cool', 'aus':'off'} %}
{{ mode_values[value_json.opmode.value] | default('off') }}
mode_state_topic: "ebusd/700/OpMode"
mode_command_template: >-
{% set values = { 'auto':'auto', 'heat':'day', 'cool':'night', 'off':'aus'} %}
{{ values[value] | default('auto') }}
mode_command_topic: "ebusd/700/OpMode/set"
value_template: "{{ value_json.tempv.value }}"
temperature_state_topic: "ebusd/700/z1ActualRoomTempDesired"
temperature_low_state_topic: "ebusd/700/z1NightTemp"
temperature_high_state_topic: "ebusd/700/z1DayTemp"
temperature_low_command_topic: "ebusd/700/z1NightTemp/set"
temperature_high_command_topic: "ebusd/700/z1DayTemp/set"
current_temperature_topic: "ebusd/bai/OutdoorstempSensor"
current_temperature_template: "{{ value_json.temp.value }}"