ludik0
June 29, 2025, 6:26pm
1
This article shall describe how to establish a modbus connection to an EuroAir Ventilation System and integrate it into Homeassistant.
I have a EuroAir350 bought in 2024 at my home and the config is tested to work with this modell.
First I bought a Waveshare TCP to Modbus adapter and connected it to the Webcontroller Clamps on the EuroAir Unit (A-A,B-B, GND-GND), as shown in this picture provided to me (via email) by EuroAir.
This video(youtube . com/watch?v=Xuj2YFZ5zME&t=96s&pp=ygUQd2F2ZXNoYXJlIG1vZGJ1cw%3D%3D) goes into detail, on how to configure the Waveshare Modbus adapter, but basically you have to switch on the waveshare modul, and download the configuration software(Vircom)
After that you can configure the following modbus settings in the Vircom software:
9600 baud
I could not find the correct slaveID anywhere in the documentation, but the company mentioned via Email it’s 10.
modbus:
- name: "lüftung"
type: tcp
host: <waveshare ip>
port: 502
sensors:
- name: "Lüftung-Außenluft"
slave: 10
address: 4
input_type: input
data_type: uint16
scale: 0.1
precision: 1
unit_of_measurement: "°C"
unique_id: central_lueftung.temp_aussenluft
- name: "Lüftung-Raumluft"
slave: 10
address: 5
input_type: input
data_type: uint16
scale: 0.1
precision: 1
unit_of_measurement: "°C"
- name: "Lüftungstufe"
address: 42
input_type: holding
data_type: uint16
slave: 10
switches:
- name: "Lüftung An/Aus"
address: 1
command_on: 1
command_off: 0
write_type: holding
slave: 10
verify:
input_type: holding
address: 1
state_on: 1
state_off: 0
- name: "Lüftung ByPass Offen/Geschlossen"
address: 31
command_on: 1
command_off: 0
write_type: holding
slave: 10
verify:
input_type: holding
address: 31
state_on: 1
state_off: 0
This Config allows you to e.g. activate the bypass using homeassitant and control the ventilation speed. I will update this post, with a full list of values and maybe even create a custom integration for the EuroAir units.
3 Likes
ludik0
June 29, 2025, 6:32pm
2
Here is the download link for vircom: https://www.waveshare.com/wiki/RS485_TO_ETH_(B)#Software_Installation ) and a screenshot of the result
1 Like
kamil02
November 18, 2025, 9:08am
3
Hi @ludik0 any progeress on this one?
I got a similar machine. Do you have a full list of Modbus registers? The list i found in the manual seems to be different, because the addresses you used do not match the ones i found in the documentation. https://www.swentibold.com/_files/ugd/cab2d0_dc6cb579ece84272b592bbadf732ffce.pdf (https://www.swentibold.com/wtwtoestellen?lang=de )
v01t
November 27, 2025, 12:58pm
4
Hi @kamil02
10.02 Swentibold - modbus v1_25_H.pdf
so just contact swentibold regarding your device if those registers didn’t match for you.
esphome relevant configuration that was defined as result of provided documentation that could be useful:
# UART for Modbus
uart:
id: uart_modbus
tx_pin: GPIO17 # Connects to DI on MAX485
rx_pin: GPIO16 # Connects to RO on MAX485
baud_rate: 9600
stop_bits: 1
parity: NONE
# Modbus
modbus:
id: modbus_hub
uart_id: uart_modbus
flow_control_pin: GPIO21 # This single pin MUST be connected to both DE and RE on the MAX485
send_wait_time: 250ms
# Define the Swentibold ventilation unit as a Modbus controller target
modbus_controller:
- id: swentibold_wtw
address: 10 # Slave ID
modbus_id: modbus_hub
update_interval: 10s
sensor:
# # Register 25: Low Speed Hours
# - platform: modbus_controller
# modbus_controller_id: swentibold_wtw
# name: "Low Speed Hours"
# address: 25
# register_type: holding
# unit_of_measurement: "h"
# icon: "mdi:clock-outline"
# # Register 26: Medium Speed Hours
# - platform: modbus_controller
# modbus_controller_id: swentibold_wtw
# name: "Medium Speed Hours"
# address: 26
# register_type: holding
# unit_of_measurement: "h"
# icon: "mdi:clock-outline"
# # Register 27: High Speed Hours
# - platform: modbus_controller
# modbus_controller_id: swentibold_wtw
# name: "High Speed Hours"
# address: 27
# register_type: holding
# unit_of_measurement: "h"
# icon: "mdi:clock-outline"
# - platform: modbus_controller
# modbus_controller_id: swentibold_wtw
# name: "Bypass temp test"
# address: 2
# register_type: holding
# unit_of_measurement: "°C"
# filters:
# - multiply: 0.1
# Register 28: Filter Hours
- platform: modbus_controller
modbus_controller_id: swentibold_wtw
name: "Filter Hours"
address: 28
register_type: holding
unit_of_measurement: "h"
icon: "mdi:air-filter"
# # Register 46: Cooling Percentage
# - platform: modbus_controller
# modbus_controller_id: swentibold_wtw
# name: "Cooling Percentage"
# address: 46
# register_type: holding
# unit_of_measurement: "%"
# icon: "mdi:coolant-temperature"
# # Register 47: Heating Percentage
# - platform: modbus_controller
# modbus_controller_id: swentibold_wtw
# name: "Heating Percentage"
# address: 47
# register_type: holding
# unit_of_measurement: "%"
# icon: "mdi:radiator"
# Internal sensor for device type (used by text_sensor below)
- platform: modbus_controller
modbus_controller_id: swentibold_wtw
id: wtw_type_raw
internal: true
address: 0 # Register 0: Type
register_type: holding
text_sensor:
# Register 0: Device Type
- platform: template
name: "Device Type"
icon: "mdi:information-outline"
lambda: |-
auto val = id(wtw_type_raw).state;
if (isnan(val)) { return {"Unknown"}; }
switch ((int)val) {
case 1: return {"Basis"};
case 2: return {"Bypass"};
case 3: return {"Comfort"};
default: return {"Unknown"};
}
binary_sensor:
# Register 29: Status (bit-mapped)
# Bit 1 = Medium vent active
- platform: modbus_controller
modbus_controller_id: swentibold_wtw
name: "Medium Ventilation"
address: 29
register_type: holding
bitmask: 0b0000000000000010 # (1 << 1)
icon: "mdi:fan-speed-2"
# Bit 2 = High vent active
- platform: modbus_controller
modbus_controller_id: swentibold_wtw
name: "High Ventilation"
address: 29
register_type: holding
bitmask: 0b0000000000000100 # (1 << 2)
icon: "mdi:fan-speed-3"
# Register 30: Digin (Digital Inputs, bit-mapped)
# Bit 2 = Hygrostat
- platform: modbus_controller
modbus_controller_id: swentibold_wtw
name: "Hygrostat"
address: 30
register_type: holding
bitmask: 0b0000000000001000 # (1 << 3)
icon: "mdi:water-percent"
# # Register 43: Recirculation status
# - platform: modbus_controller
# modbus_controller_id: swentibold_wtw
# name: "Recirculation Status"
# address: 43
# register_type: holding
# device_class: opening
# # Register 44: Cooling status
# - platform: modbus_controller
# modbus_controller_id: swentibold_wtw
# name: "Cooling Status"
# address: 44
# register_type: holding
# device_class: running
# # Register 45: Heating status
# - platform: modbus_controller
# modbus_controller_id: swentibold_wtw
# name: "Heating Status"
# address: 45
# register_type: holding
# device_class: heat
# # Register 40: Error status bits
# # You can add one for each bit you want to monitor
# - platform: modbus_controller
# modbus_controller_id: swentibold_wtw
# name: "Fault E1"
# address: 40
# register_type: holding
# bitmask: 2
# device_class: problem
# - platform: modbus_controller
# modbus_controller_id: swentibold_wtw
# name: "Fault Ft"
# address: 40
# register_type: holding
# bitmask: 256
# device_class: problem
select:
# Register 1: On/Off
- platform: modbus_controller
modbus_controller_id: swentibold_wtw
name: "Power"
address: 1
optionsmap:
"Off": 0
"On": 1
icon: "mdi:power"
# Register 8: Filter time reset
- platform: modbus_controller
modbus_controller_id: swentibold_wtw
name: "Filter Time Reset"
address: 8
optionsmap:
"No": 0
"Yes": 1
icon: "mdi:filter-remove-outline"
# Register 23: Summer/Winter Time
- platform: modbus_controller
modbus_controller_id: swentibold_wtw
name: "Automatic Summer/Winter Time"
address: 23
optionsmap:
"Disabled": 0
"Enabled": 1
icon: "mdi:calendar-sync"
# Register 24: Holiday Mode
- platform: modbus_controller
modbus_controller_id: swentibold_wtw
name: "Holiday Mode"
address: 24
optionsmap:
"Disabled": 0
"Enabled": 1
icon: "mdi:palm-tree"
# Register 31: Bypass
- platform: modbus_controller
modbus_controller_id: swentibold_wtw
name: "Bypass"
address: 31
optionsmap:
"Closed": 0
"Open": 1
icon: "mdi:swap-horizontal"
# Register 32: Earth cooling
- platform: modbus_controller
modbus_controller_id: swentibold_wtw
name: "Earth Cooling"
address: 32
optionsmap:
"Closed": 0
"Open": 1
icon: "mdi:earth-arrow-right"
# Register 42: Ventilation Mode
- platform: modbus_controller
modbus_controller_id: swentibold_wtw
name: "Ventilation Mode"
address: 42
optionsmap:
"Auto": 0
"Low": 1
"Medium": 2
"High": 3
icon: "mdi:fan"
switch:
- platform: restart
name: ${device_name} restart
number:
# Register 2: Bypass Temperature Setpoint
# Probably FW issue - value * 10 (e.g. 150: 15°C)
- platform: modbus_controller
modbus_controller_id: swentibold_wtw
name: "Bypass Temperature Setpoint"
address: 2
unit_of_measurement: "°C"
mode: slider
step: 10
min_value: 150
max_value: 300
icon: "mdi:thermometer"
# Register 3: Recirculation temperature
- platform: modbus_controller
modbus_controller_id: swentibold_wtw
name: "Recirculation Temperature Setpoint"
address: 3
unit_of_measurement: "°C"
mode: slider
step: 1
min_value: -10
max_value: 30
icon: "mdi:thermometer"
# Register 4: Comfort Temperature Setpoint
- platform: modbus_controller
modbus_controller_id: swentibold_wtw
name: "Comfort Temperature Setpoint"
address: 4
unit_of_measurement: "°C"
mode: slider
step: 1
min_value: 15
max_value: 30
icon: "mdi:home-thermometer-outline"
# Register 5: Hygrostat Switch-On Delay
- platform: modbus_controller
modbus_controller_id: swentibold_wtw
name: "Hygrostat Switch-On Delay"
address: 5
unit_of_measurement: "m"
mode: slider
step: 1
min_value: 0
max_value: 120
icon: "mdi:timer-plus-outline"
# Register 6: Hygrostat Switch-Off Delay
- platform: modbus_controller
modbus_controller_id: swentibold_wtw
name: "Hygrostat Switch-Off Delay"
address: 6
unit_of_measurement: "m"
mode: slider
step: 1
min_value: 0
max_value: 120
icon: "mdi:timer-minus-outline"
# Register 7: Filter Change Interval
- platform: modbus_controller
modbus_controller_id: swentibold_wtw
name: "Filter Change Interval"
address: 7
unit_of_measurement: "w"
mode: slider
step: 1
min_value: 1
max_value: 99
icon: "mdi:calendar-clock"
* some registers are commented just because they have no affect in my case
Hope that will help others to make their ventilation system more smarter
