--- title: "Helios easyControls 3.0" description: "Helios easyControls 3.0 Modbus RTU integration for KWL ventilation units with heat recovery." url: "https://taphome.com/en/compatibility/helios-easycontrols/" language: en lastmod: 2026-03-20 generator: hugo ai: topics: ["modbus-rtu","air-recovery","rs485","heat-recovery","ventilation","co2-sensor","humidity-sensor"] questions: ["How to integrate Helios easyControls 3.0 with TapHome?","What does the Helios easyControls TapHome template control?","How to connect Helios KWL ventilation unit via RS-485 to TapHome?","How to configure Modbus RTU settings on Helios easyControls?","How to set up CO2 and humidity-based ventilation control via TapHome?","What ventilation profiles can be controlled via Modbus on Helios KWL?"] --- # Helios easyControls 3.0 Communication: Modbus RTU - [Helios KWL Product Page](https://www.heliosventilatoren.de/en/products/ventilation-with-heat-recovery/domestic-units-for-wall-ceiling-installation/helios-kwl-r-with-easycontrols-3-0) - [Helios Official Website](https://www.heliosventilatoren.de) The Helios easyControls 3.0 is a building control system interface for Helios KWL ventilation units with heat recovery. It communicates with TapHome via Modbus RTU over RS-485, providing access to CO2 and humidity sensor readings, fan speed monitoring and configuration, ventilation mode switching (Home, Away, Boost, Fireplace), and timer management. The system uses holding registers in the range H:4353 to H:21772. Temperature values are transmitted in centiKelvin (cK), where 0 degrees C equals 27315 cK. ## Hardware connection ### RS-485 wiring The Helios KWL unit exposes an RS-485 Modbus RTU interface on its PCB terminal block. Multiple units can be daisy-chained on the same bus with a 120 ohm termination resistor on the last unit. ![Helios easyControls Modbus RTU RS-485 wiring diagram showing master-slave daisy chain with 120 ohm termination](https://taphome.com/images/compatibility/helios-easycontrols/wiring-diagram-p012_hu_1cffa3d98f911e8b.jpg) Connect using a **3-wire RS-485 connection** to the KWL unit's terminal block: - **MB_A** (Data+) to A+/D+ on TapHome RS-485 - **MB_B** (Data-) to B-/D- on TapHome RS-485 - **GND** to GND on TapHome power supply The last unit on the bus requires a **120 ohm termination resistor** between MB_A and MB_B. > [!WARNING] > **Important -- Grounding** > > The GND wire **must** be connected between the Helios unit and the TapHome power supply. Without proper grounding, communication errors may occur. ## Configuration ### Enabling Modbus communication The Modbus RTU default settings can be changed via the **KWL-BE Touch** panel or via the unit's **internal web server**. ![Helios easyControls 3.0 Modbus settings screen showing address, baud rate, parity and stop bit configuration](https://taphome.com/images/compatibility/helios-easycontrols/modbus-settings-p009_hu_bbb97d298672ea21.jpg) **Default Modbus parameters:** | Parameter | Default value | |-----------|--------------| | **Address** | 1 | | **Baud rate** | 19200 | | **Parity** | Even | | **Stop bit** | 1 | **Configure TapHome to match:** Set the RS-485 bus to 19200 baud, even parity, 1 stop bit. Use Slave ID 1 (or the address configured on the unit). ### Profile priority If more than one profile is active simultaneously, the profile with higher priority overrides the lower-priority profile. The priority order (highest to lowest) is: 1. **Timer configurable input** (assigned to digital inputs) 2. **Fireplace function** 3. **Boost ventilation** 4. **Home/Away** For example, if both the fireplace function and boost ventilation profiles are active at the same time, the fireplace function overrides the boost ventilation due to its higher priority. ## Device capabilities ### CO2 monitoring **CO2 Value** (H:4364) reads the highest CO2 measurement across all connected CO2 sensors in PPM. If no CO2 sensor is connected, the value reads 0 and a warning is generated in TapHome. The device exposes seven service attributes: - **CO2 Sensor 0 through CO2 Sensor 5** (H:4379 to H:4384) -- individual sensor readings in PPM. A value of 65535 indicates no sensor connected at that position. - **CO2 Threshold** (H:20491) -- the current CO2 control threshold (range 500 to 2000 PPM). A service action **CO2 Threshold** allows setting the CO2 threshold value for automatic ventilation adjustment. ### Fan speed monitoring and profiles **Fan Speed** (H:4353) displays the current fan speed as a percentage (0 to 100%). This represents the actual running speed of the ventilation unit. Service attributes expose the configured fan speeds for each profile: - **Away Fan Speed** (H:20501) -- fan speed in Away profile - **Home Fan Speed** (H:20507) -- fan speed in Home profile - **Boost Fan Speed** (H:20513) -- fan speed in Boost profile - **Boost Air Target Temperature** (H:20514) -- supply air target temperature in Boost profile (centiKelvin to degrees C conversion) - **Boost CO2 Control** and **Boost RH Control** (H:20512, H:20511) -- enable/disable CO2 and humidity-based automatic adjustment in Boost mode Two service actions allow configuring fan parameters: - **Fan Speed Setup** -- sets fan speed percentages for Home, Away and Boost profiles simultaneously - **Boost Set Up** -- configures the Boost profile including fan speed, supply air target temperature, and CO2/RH control toggles ### Internal sensor (temperature and humidity) **Internal Sensor** (H:4369/H:4370) reads temperature and relative humidity from the built-in multisensor. The temperature uses 12-bit internal encoding and the humidity is divided by 100 to get the percentage value. This device exposes extensive service attributes for monitoring the ventilation system: **Air temperatures** (all in centiKelvin, converted to degrees C): - **Extract Air Temperature** (H:4354) -- air entering the heat recovery cell from indoors - **Exhaust Air Temperature** (H:4355) -- air leaving the heat recovery cell to outdoors - **Outdoor Air Temperature** (H:4356) -- fresh air entering the unit from outside - **Supply Air Temperature** (H:4358) -- conditioned air delivered to rooms after the heater **Humidity sensors:** - **RH Sensor 0 through RH Sensor 5** (H:4373 to H:4378) -- individual relative humidity readings in percent. A value of 65535 indicates no sensor connected. - **RH Basic Level** (H:20490) -- the calculated or manually set RH basic level (65535 if not yet calculated) - **RH Level Mode** (H:20543) -- 0 for Automatic Level Update, 1 for Manual **System status:** - **Cell State** (H:4616) -- heat recovery cell operation: 0 = Heat Recovery, 1 = Cool Recovery, 2 = Bypass, 3 = Defrosting - **Filter Change Date** (H:20546 to H:20548) -- last filter change date (day, month, year) - **Filter Change Interval** (H:20537) -- interval in days for the filter change indicator (30 to 365) Service actions on the Internal Sensor device: - **Filter Change Date** -- records a new filter change date - **RH Basic Level** -- sets the humidity reference level (0 to 100%) - **RH Level Mode** -- selects automatic or manual humidity level control ### Ventilation mode control **Mode** (H:4609) is a multi-value switch controlling the ventilation profile with four states: | Value | Mode | Description | |-------|------|-------------| | 0 | **Home** | Normal ventilation with home profile settings | | 1 | **Away** | Reduced ventilation for unoccupied periods | | 2 | **Boost** | Intensive ventilation (timer-based via H:21766) | | 3 | **Fireplace** | Positive-pressure mode for homes with a fireplace (timer-based via H:21767) | The Mode device exposes twelve service attributes showing per-profile configuration: - **Away** settings: fan speed, supply air target, RH control, CO2 control - **Home** settings: fan speed, supply air target, RH control, CO2 control - **Fireplace** fan speeds: separate extract and supply fan speed percentages - **Weekly Timer** state (enabled/disabled) and **WeekDay** (1 = Monday through 7 = Sunday) Five service actions allow full profile configuration: - **Away Set Up** / **Home Set Up** -- configures fan speed, supply air target temperature, RH and CO2 control for each profile - **Fan Speed Setup** -- sets Home, Away, and Boost fan speed percentages simultaneously - **Fireplace Set Up** -- configures extract and supply fan speeds for fireplace mode - **Weekly Timer** -- enables or disables the weekly timer program ### Module-level service diagnostics The module exposes nine service attributes for system monitoring: - **Date** and **Time** -- current unit clock (day, month, year, hours, minutes) - **Fireplace Timer** and **Fireplace Time** -- fireplace mode timer state and duration in minutes - **Boost Timer** and **Boost Time** -- boost ventilation timer state and duration in minutes - **Extra Timer** -- configurable digital input timer state - **Weekly Timer** -- weekly program state (enabled/disabled) - **Filter Change Date** -- last filter change date Four module-level service actions: - **Set Date and Time** -- sets the unit clock (year, month, day, hour, minute) - **Timers Control** -- toggles boost, fireplace, and extra timers on/off - **Timers Set Up** -- configures boost and fireplace timer durations (1 to 1440 minutes) - **Filter Change** -- records a filter change date ### Additional capabilities The Helios easyControls 3.0 also exposes registers for four individual air temperatures (outdoor, extract, exhaust, supply) as standalone sensor devices, a separate RH aggregate value, an optional external temperature sensor (H:4389), and boost/fireplace timer remaining time counters. These are currently available as service attributes on the Internal Sensor and Mode devices. They can be added as standalone TapHome devices in a future template update. > [!TIP] > The four air temperature sensors (outdoor, extract, exhaust, supply) are accessible as service attributes on the Internal Sensor device. If standalone temperature devices are needed, they can be added as custom Modbus devices in TapHome using the corresponding register addresses with centiKelvin-to-Celsius conversion (subtract 27315, divide by 100). ## Troubleshooting ### No Modbus communication 1. **Check RS-485 cables:** - MB_A correctly connected to A+/D+ on TapHome - MB_B correctly connected to B-/D- on TapHome - **GND connected to TapHome power supply ground** -- most common issue 2. Verify the Modbus Slave address matches the unit configuration (default: 1) 3. Check the 120 ohm termination resistor on the last unit 4. Confirm TapHome is set to: **19200 baud, even parity, 1 stop bit** 5. Measure voltage between MB_A and MB_B -- should be 1.5 to 5 V at idle ### CO2 or RH sensor warnings If TapHome shows "No CO2 sensor" or "No RH sensor" warnings: 1. Verify the external CO2/RH sensors are physically connected to the KWL unit 2. Check individual sensor readings in the service attributes (CO2 Sensor 0 through 5, RH Sensor 0 through 5) -- a value of 65535 indicates no sensor at that position 3. If all sensors show 65535, check the sensor wiring at the KWL terminal block ### Temperature readings incorrect Temperature values are transmitted in centiKelvin. If readings appear as large numbers (e.g., 29315 instead of 20 degrees C): 1. Verify TapHome is applying the conversion correctly 2. The correct formula is: **Temperature in degrees C = (cK value - 27315) / 100** 3. Valid range for temperature registers is 21000 to 33224 cK (approximately -63 degrees C to +59 degrees C) ### easyControls 2.0 compatibility The easyControls 2.0 system uses a non-standard Modbus TCP/IP protocol with ASCII-encoded variable names. It is **not compatible** with this template or with standard TapHome Modbus integration. Only easyControls 3.0 units with Modbus RTU support can use this template. ## Available devices Helios easyControls 3.0 Module Service Attributes | | | |--------------------|---------------------------------------------| | Date | | | Time | | | Fireplace Timer | | | Fireplace Time | Fireplace timer duration in minutes | | Boost Timer | | | Boost Time | Boost ventilation timer duration in minutes | | Extra Timer | Configurable digital input timer state | | Weekly Timer | | | Filter Change Date | | Service Actions | | | |-------------------|--------------------------------------------------------------------| | Set Date and Time | | | Timers Control | Toggles boost, fireplace and extra timers on or off | | Timers Set Up | Configures boost and fireplace timer durations (1 to 1440 minutes) | | Filter Change | Records the date of a filter replacement | CO2 Value Dimmer Read-only Highest CO2 measurement across all connected sensors in PPM — warns if no sensor is connected Register: H:4364 UInt16 Unit: PPM numeric Service Attributes | | | |---------------|------------------------------------------------------------------------------| | CO2 Sensor 0 | | | CO2 Sensor 1 | | | CO2 Sensor 2 | | | CO2 Sensor 3 | | | CO2 Sensor 4 | | | CO2 Sensor 5 | | | CO2 Threshold | CO2 control threshold for automatic ventilation adjustment (500 to 2000 PPM) | Service Actions | | | |---------------|----------------------------------------------------------| | CO2 Threshold | Sets the CO2 threshold for automatic ventilation control | Fan Speed Dimmer Read-only Current ventilation fan speed as percentage (0 to 100%) Register: H:4353 UInt16 Unit: % numeric Service Attributes | | | |------------------------------|------------------------------------------------| | Away Fan Speed | | | Home Fan Speed | | | Boost Fan Speed | | | Boost Air Target Temperature | Supply air target temperature in Boost profile | | Boost CO2 Control | | | Boost RH Control | | Service Actions | | | |-----------------|-----------------------------------------------------------------------------| | Boost Set Up | Configures Boost profile — fan speed, supply air target, RH and CO2 control | | Fan Speed Setup | Sets fan speed percentages for Home, Away and Boost profiles | Internal Sensor Temperature Sensor Read-only Built-in temperature and humidity multisensor with air quality monitoring, filter status and heat recovery cell state Register: H:4369 Int16 Unit: °C numeric Service Attributes | | | |-------------------------|------------------------------------------------------------------------------------| | Filter Change Date | | | Filter Change Interval | Days between filter change reminders (30 to 365) | | Cell State | Heat recovery cell operation — Heat Recovery, Cool Recovery, Bypass, or Defrosting | | Exhaust Air Temperature | Air leaving the heat recovery cell to outdoors | | Extract Air Temperature | Air entering the heat recovery cell from indoors | | Outdoor Air Temperature | Fresh air entering the unit from outside | | Supply Air Temperature | Conditioned air delivered to rooms after the heater | | RH Sensor 0 | | | RH Sensor 1 | | | RH Sensor 2 | | | RH Sensor 3 | | | RH Sensor 4 | | | RH Sensor 5 | | | RH Basic Level | Humidity reference level for automatic ventilation control | | RH Level Mode | Automatic or manual humidity level control | Service Actions | | | |--------------------|-----------------------------------------------| | Filter Change Date | Records the date of a filter replacement | | RH Basic Level | Sets the humidity reference level (0 to 100%) | | RH Level Mode | | Mode Multi-value Switch Ventilation profile selector — Home, Away, Boost, or Fireplace mode with per-profile fan speed and air quality settings Register: H:4609 UInt16 multi-register Values / States: Home · Away · Boost · Fireplace Service Actions | | | |------------------|----------------------------------------------------------------------------| | Weekly Timer | Enables or disables the weekly timer program | | Away Set Up | Configures Away profile — fan speed, supply air target, RH and CO2 control | | Home Set Up | Configures Home profile — fan speed, supply air target, RH and CO2 control | | Fan Speed Setup | Sets fan speed percentages for Home, Away and Boost profiles | | Fireplace Set Up | Configures extract and supply fan speeds for Fireplace mode | **Connection:** Modbus RTU • 19200 baud• 8E1 • Slave ID: $\[SlaveId] Possible improvements (8) - H:4356 Outdoor Air Temperature (as device) — TEMP\_OUTDOOR\_AIR — exposed only as service attribute on Internal Sensor, not as standalone temperature device - H:4354 Extract Air Temperature (as device) — TEMP\_EXTRACT\_AIR — exposed only as service attribute on Internal Sensor, not as standalone temperature device - H:4355 Exhaust Air Temperature (as device) — TEMP\_EXHAUST\_AIR — exposed only as service attribute on Internal Sensor, not as standalone temperature device - H:4358 Supply Air Temperature (as device) — TEMP\_SUPPLY\_AIR — exposed only as service attribute on Internal Sensor, not as standalone temperature device - H:4363 RH Value (as device) — RH\_VALUE — highest RH measurement across sensors. Only used for warning check in readscript, not as standalone humidity device - H:4389 Optional External Temperature Sensor — TEMP\_OPTIONAL in centiKelvin — not used in template - H:4612 Boost Timer Remaining Time — Remaining minutes for boost ventilation timer (65535=duration active). Not exposed as sensor device - H:4613 Fireplace Timer Remaining Time — Remaining minutes for fireplace mode timer (65535=duration active). Not exposed as sensor device ## Sources - [PDF](https://taphome.com/compatibility/devices/helios-easycontrols/manufacturer/easycontrols-3.0-modbus-rtu.md) - [PDF](https://taphome.com/compatibility/devices/helios-easycontrols/manufacturer/easycontrols-2.0-modbus-tcp.md) - https://www.heliosventilatoren.de/en/products/ventilation-with-heat-recovery/domestic-units-for-wall-ceiling-installation/helios-kwl-r-with-easycontrols-3-0 [www.heliosventilatoren.de](https://www.heliosventilatoren.de/en/products/ventilation-with-heat-recovery/domestic-units-for-wall-ceiling-installation/helios-kwl-r-with-easycontrols-3-0) ## Related Documentation - [Modbus Integration](https://taphome.com/en/compatibility/modbus-guide/) - [Modbus](https://taphome.com/en/docs/integration/modbus/) - [Simple configuration using templates](https://taphome.com/en/docs/integration/modbus/templates/) - [Modbus scripts and prefetch](https://taphome.com/en/docs/script/modbus-scripts/) - [Modbus functions](https://taphome.com/en/docs/script/modbus/) - [Modbus data types](https://taphome.com/en/docs/script/modbus-data-types/)