Wolf CWL Excellent
Controls Wolf CWL Excellent ventilation units via Modbus RTU
This template connects to the Wolf CWL Excellent ventilation unit via Modbus RTU at 9600 baud. It reads temperatures, airflow, pressures, bypass and preheater status, filter condition, and CO2 levels. It also allows control of flowrate, bypass mode, geo heat exchanger settings, and filter reset.
- Protocol
- Modbus RTU
- Connection
- RS485, 9600 baud
- Registers
- 34, read and write
- Brand
- Wolf
- Key readings
- Outside and dwelling temperature · Supply and exhaust duct pressure · Supply and exhaust flowrate · Bypass valve position and status · Preheater status and power · Filter status and CO2 sensor value
- Available commands
- Set flowrate · Bypass control mode and value · Geo heat exchanger mode and temps · Filter reset
- Compatible models
- Wolf CWL Excellent
- Last updated
Registers (34)
22 read, 12 write
| Name | Unit | Access | Address (Hidden until you enter your email) | Function (hidden) | Type (hidden) |
|---|---|---|---|---|---|
| 4011_Current pressure suppy duct [Pa] | Pa | Read | |||
| 4013_Preset air flowrate [m³_h] | m³/h | Read | |||
| 4009_Current Temperature from outside sensor [°C] | °C | Read | |||
| 4012_Current pressure exhaust duct [Pa] | Pa | Read | |||
| 4002_Appliance type | Read | ||||
| 4004_Appliance version (basic_plus) | Read | ||||
| 4010_Current Temperature from dwelling[°C] | °C | Read | |||
| 4028_Current supply flowrate [m²_h] | m³/h | Read | |||
| 4029_Current exhaust flowrate [m³_h] | m³/h | Read | |||
| 4030_Bypass valve position | Read | ||||
| 4031_Operation bypass valve | Read | ||||
| 4037_Preheater status | Read | ||||
| 4038_Preheater power | W | Read | |||
| 4039_Current fault code | Read | ||||
| 4040_Filter status | Read | ||||
| 4016_Imbalance permissible | Read | ||||
| 4022_Preset imbalance [m³_h] | Read | ||||
| 4041_Geo heater exchange mode | Read | ||||
| 4047_Geo heater exchange min. temp. [°C] | °C | Read | |||
| 4053_Geo heater exchange max temp. [°C] | °C | Read | |||
| 4059_No selected CO² Sensor (max 4) | count | Read | |||
| 4060_Value selected CO² Sensor [PPM] | PPM | Read | |||
| 6013_Set control mode Bypass | Write | ||||
| 6001_Value flowrate [m³_h] | Write | ||||
| 6006_Operation Bypass value | Write | ||||
| 6004_Imbalance permissible | Write | ||||
| 6012_Reset Wolf appliance | Write | ||||
| 6011_CO2 Sensor read out | ppm | Write | |||
| 6010_Geo heat exchanger max temp.[C°] | °C | Write | |||
| 1000_Modbus Slave-Adress | Write | ||||
| 6005_Preset imbalance [m³_h] | Write | ||||
| 6007_Filter Reset | Write | ||||
| 6008_Geo heat exchanger mode | Write | ||||
| 6009_Geo heat exchanger min temp.[C°] | °C | Write |
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Use cases
- Monitor outside and dwelling temperatures alongside supply and exhaust airflow on a live cloud dashboard.
- Create an alert when the filter status indicates a clogged filter so you can schedule maintenance proactively.
- Adjust target flowrate remotely to match seasonal occupancy changes in residential buildings.
- Track CO2 sensor values over time to verify that ventilation rates meet indoor air quality standards.
- Configure bypass valve mode and geo heat exchanger settings remotely after commissioning without a site visit.
- Trigger a filter reset from the cloud dashboard after a filter replacement has been completed on site.
Installation
Install the Wolf Modbus interface module in the CWL Excellent unit and connect it to the RS-485 port on your ModbusCloud Gateway using twisted pair wiring with correct A/B polarity.
Set the Modbus slave address on the Wolf unit to a unique value on the bus, and note this address for configuration in ModbusCloud.
Configure the serial port on the ModbusCloud gateway to 9600 baud, 8 data bits, odd parity, and 1 stop bit to match the Wolf CWL Excellent settings.
Import the Wolf CWL Excellent template from the ModbusCloud template library and assign the correct slave address.
Verify communication by checking that live values such as outside temperature and supply flowrate appear on the ModbusCloud dashboard.
Remember that register addresses are offset by 1 from Wolf label numbers, so label 4011 maps to address 4010 in the template.
Things to watch for
I see no data after connecting the gateway. What should I check?
Verify that the RS-485 A and B lines are not swapped and that the baud rate is set to 9600 with odd parity on both the gateway and the Wolf unit. Also confirm the correct Modbus slave address is configured in the template.
Why do temperature readings appear as very large or negative numbers?
Temperature registers on the Wolf CWL Excellent are signed int16 values. Make sure your gateway and template interpret these registers as signed integers, not unsigned. The template is preconfigured for this, but manual edits may have changed the data type.
How do I know which register address to use if I want to add custom registers?
Wolf documentation uses label numbers that are offset by 1 from the actual Modbus addresses. Subtract 1 from the label number to get the correct register address. For example, label 4011 corresponds to address 4010.
Does the Wolf CWL Excellent support Modbus RTU out of the box?
No, you need the optional Wolf Modbus interface module installed in the unit. Without this module, the RS-485 connection is not available.
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