Hoval Ventilation
Controls Hoval TopTronic E ventilation systems via Modbus TCP or RTU.
This template connects Hoval HomeVent ventilation units with TopTronic E controls to ModbusCloud via Modbus RTU or TCP. It reads supply and extract air temperatures, humidity, VOC levels, and airflow data. It also allows remote control of operating mode, humidity setpoint, and ventilation modulation.
- Protocol
- Modbus RTU
- Connection
- RS485, 19200 baud
- Registers
- 12, read and write
- Brand
- Hoval
- Key readings
- Supply air temperature · Extract air temperature · Airflow setpoint and actual (%) · Extract air humidity (%) · VOC extract and outdoor air (%) · Ventilation regulation status
- Available commands
- Betriebsart (operating mode) · Humidity setpoint · Normal ventilation modulation · Eco ventilation modulation
- Compatible models
- HomeVent FR · HomeVent FRT · HomeVent ER · HomeVent ERT
- Last updated
Registers (12)
8 read, 4 write
| Name | Unit | Access | Address (Hidden until you enter your email) | Function (hidden) | Type (hidden) |
|---|---|---|---|---|---|
| Temperatur Abluft | °C | Read | |||
| Luftmenge Soll | % | Read | |||
| Status ventilation regulation | Read | ||||
| Temperatur Zuluft | °C | Read | |||
| VOC Abluft | % | Read | |||
| Feuchtigkeit Abluft | % | Read | |||
| VOC Außenluft | % | Read | |||
| Luftmenge Ist | % | Read | |||
| Feuchtigkeitssollwert | % | Write | |||
| Betriebsart Lüftung | Write | ||||
| Lüftungsmodulation Normal Betrieb | % | Write | |||
| Lüftungsmodulation Eco Betrieb | % | Write |
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If a device is not in the library yet, we build the template for free as soon as we have the register data.
Use cases
- Monitor supply and extract air temperatures on a live dashboard to verify heat recovery performance.
- Create an alert when extract air humidity exceeds the setpoint for more than 15 minutes.
- Track VOC levels in extract and outdoor air to document indoor air quality for building reports.
- Remotely switch between normal and eco ventilation mode to reduce energy consumption outside occupancy hours.
- Adjust ventilation modulation setpoints from the cloud to align fan speed with solar energy availability.
- Log airflow percentages over time to identify maintenance needs such as clogged filters.
Installation
Activate Modbus communication in the Hoval TopTronic E control unit and note the assigned slave address.
Connect the Hoval Connect Modbus Gateway to the ModbusCloud Gateway using a shielded twisted pair cable for RS-485 (Modbus RTU) or an Ethernet cable for Modbus TCP.
Set the baud rate to 19200 and parity to odd on the ModbusCloud gateway to match the Hoval default settings.
Import the Hoval Ventilation template from the ModbusCloud template library and assign it to the correct gateway and slave address.
Verify that live readings such as supply air temperature and airflow percentage appear on the ModbusCloud dashboard.
If multiple Hoval devices share the same CAN bus, confirm that each device uses a unique register address range to avoid conflicts.
Things to watch for
I see no data after connecting. What should I check first?
Confirm that Modbus is activated inside the TopTronic E control unit. This setting is not enabled by default. Also verify the slave address matches what you configured in ModbusCloud.
What baud rate and parity does the Hoval HomeVent expect?
The default is 19200 baud with odd parity (1 stop bit). Make sure the ModbusCloud gateway serial port uses the same settings.
Can I use one Modbus gateway for multiple Hoval devices on the same CAN bus?
Yes. If several Hoval heat generators or ventilation units share a CAN bus, a single Modbus gateway can address them all. Each device uses a different register address range starting around 23622 for the HomeVent.
Where can I find the exact register map for my HomeVent model?
Hoval provides model-specific register documentation through their local departments. Contact Hoval support to request the Modbus register list for your HomeVent FR, FRT, ER, or ERT unit.
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