Controlling Wolf Ventilation Unit CWL 400

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Drchandra
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Controlling Wolf Ventilation Unit CWL 400

Post by Drchandra »

Hello,
two statements before I start: 1. I'm not an English native Speaker, but German 2. I'm no software specialist, only a simple retired orthopedic surgeon.

I own a ventilation unit Wolf CWL 400 which is obviously built by a dutch company and sold under several different brands like Wolf or Viessmann. The unit is a little older already and has no native digital connectivity (except OpenTherm), it's not a "smart" device. I would like to control it by smarthome applications like OpenHAB or IO-Broker, not only to monitor different values, but to control values like ventilation rate, bypass on/off, switching the unit on/off. My first step was to buy the Opentherm Gateway and to connect it to my ventilation unit. It works pretty well meanwhile, and with Opentherm Monitor I am able to read and save a log file which lists hundreds of numbers and letters. Some of the parameters I understand are "Room temperature", "Supply inlet temperature", "Exhaust inlet temperature" and "Relative ventilation". The last value changes when I change the ventilation rate on the thermostat unit. With 160 m3/h the "Relative ventilation" value is 59. It rises to about 70 with 250 m3/h and decreases to about 30 with 75m3/h.

That's all I can do until now. My goal is to change the ventilation rate, for example depending on the CO2 Concentration in my living room, or to shut off the ventilation unit when my fine dust sensor detects pollution outside. The functionality should be integrated in smarthome apps like OpenHAB. I know there is an Opentherm Binding for OpenHAB, and I will post this topic in the corresponding OpenHAB forum, too.

Is there anyone who can give me advice how to proceed? Or is there a solution already?

Best regards
Michael
hvxl
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Re: Controlling Wolf Ventilation Unit CWL 400

Post by hvxl »

The OTGW has a VS command to change the ventilation setpoint. You can try that from OTmonitor to see if it has the desired effect. There currently is no command to completely switch off the ventilation. I suppose that would involve manipulating ID70:HB0. But it is difficult for me to develop such functionality, as I don't have access to a ventilation unit.
Schelte
Drchandra
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Re: Controlling Wolf Ventilation Unit CWL 400

Post by Drchandra »

Perfect, it works! Many thanks!
Michael
Drchandra
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Re: Controlling Wolf Ventilation Unit CWL 400

Post by Drchandra »

Two years later - after an interruption I‘m still dealing with the problem. It‘s true: you can send commands like VS=50, VS=100 or even VS=0 - the ventilation rate changes - so far, so good. But once you have sent a command like this you can‘t control the unit by the thermostat anymore. To be able to do that again you have to reset the OTGW.

Looking into the firmware description you‘ll see that the VS command obviously overrides the setting permanently, but it should be possible to reset it by sending a VS command with a non-numeric value. I tried values like VS=AA, VS=XX or VS=__, but nothing could override the setting that was sent previously with a VS command with a numeric value.

Michael
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Re: Controlling Wolf Ventilation Unit CWL 400

Post by hvxl »

I don't have the equipment to be able to test this in real life. But looking at the variables when I run these commands, I see no reason why it wouldn't work.

If your gateway is more than 2 years old, I'm assuming you use FW 5.5, rather than 6.2. In that case, please provide a log where you do the following steps:
  1. Issue the command DP=46
  2. Set a ventilation setpoint using the VS command, e.g. VS=15
  3. Wait for a MsgID71 to be sent by the thermostat
  4. Cancel the ventilation setpoint using one of your commands, e.g. VS=XX
  5. Wait for a MsgID71 to be sent by the thermostat
You can compress the log file using (g)zip and attach it to your response.
Schelte
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Re: Controlling Wolf Ventilation Unit CWL 400

Post by hvxl »

I ran the scenario in the simulator. That also shows the expected behavior: Initially the thermostat requests a V/H setpoint of 20. After a VS=15 command, the OTGW overrides the thermostat and send a V/H setpoint of 15 to the boiler. Finally, following a VS=XX command, the OTGW no longer overrides the command from the thermostat and the V/H setpoint of 20 is forwarded to the boiler again.

Code: Select all

17:32:15.447819  T80000200  Read-Data   Status: 00000010 00000000
17:32:15.654425  B4000020C  Read-Ack    Status: 00000010 00001100
17:32:16.475816  T10010A00  Write-Data  Control setpoint: 10.00
17:32:16.673278  BD0010A00  Write-Ack   Control setpoint: 10.00
17:32:17.469672  T100E0000  Write-Data  Maximum relative modulation level: 0.00
17:32:17.660649  BD00E0000  Write-Ack   Maximum relative modulation level: 0.00
17:32:18.436839  T00120000  Read-Data   CH water pressure: 0.00
17:32:18.633112  BC012021A  Read-Ack    CH water pressure: 2.10
17:32:19.467831  T80190000  Read-Data   Boiler water temperature: 0.00
17:32:19.676330  BC0192B80  Read-Ack    Boiler water temperature: 43.50
17:32:20.448648  T001B0000  Read-Data   Outside temperature: 0.00
17:32:20.652340  BF01B0000  Unk-DataId  Outside temperature: 0.00
17:32:21.408828  T801C0000  Read-Data   Return water temperature: 0.00
17:32:21.599911  BC01C2780  Read-Ack    Return water temperature: 39.50
17:32:22.436157  T90470014  Write-Data  Control setpoint V/H: 20
17:32:22.637541  B50470014  Write-Ack   Control setpoint V/H: 20
17:32:23.397172  T80000200  Read-Data   Status: 00000010 00000000
17:32:23.588125  B4000020C  Read-Ack    Status: 00000010 00001100
17:32:24.427905  T10010A00  Write-Data  Control setpoint: 10.00
17:32:24.630652  BD0010A00  Write-Ack   Control setpoint: 10.00
17:32:25.418471  T100E0000  Write-Data  Maximum relative modulation level: 0.00
17:32:25.624906  BD00E0000  Write-Ack   Maximum relative modulation level: 0.00
17:32:25.740189  VS: 15
17:32:26.429125  T00120000  Read-Data   CH water pressure: 0.00
17:32:26.627287  BC012021A  Read-Ack    CH water pressure: 2.10
17:32:27.394650  T80190000  Read-Data   Boiler water temperature: 0.00
17:32:27.586297  BC0192B80  Read-Ack    Boiler water temperature: 43.50
17:32:28.367217  T001B0000  Read-Data   Outside temperature: 0.00
17:32:28.572361  BF01B0000  Unk-DataId  Outside temperature: 0.00
17:32:29.395169  T801C0000  Read-Data   Return water temperature: 0.00
17:32:29.585828  BC01C2780  Read-Ack    Return water temperature: 39.50
17:32:30.415560  T90470014  Write-Data  Control setpoint V/H: 20
17:32:30.456023  R9047000F  Write-Data  Control setpoint V/H: 15
17:32:30.623921  B5047000F  Write-Ack   Control setpoint V/H: 15
17:32:30.665763  A50470014  Write-Ack   Control setpoint V/H: 20
17:32:31.399109  T80000200  Read-Data   Status: 00000010 00000000
17:32:31.591293  B4000020C  Read-Ack    Status: 00000010 00001100
17:32:32.433206  T10010A00  Write-Data  Control setpoint: 10.00
17:32:32.625602  BD0010A00  Write-Ack   Control setpoint: 10.00
17:32:33.408342  T100E0000  Write-Data  Maximum relative modulation level: 0.00
17:32:33.617233  BD00E0000  Write-Ack   Maximum relative modulation level: 0.00
17:32:34.429054  T00120000  Read-Data   CH water pressure: 0.00
17:32:34.619524  BC012021A  Read-Ack    CH water pressure: 2.10
17:32:35.471373  T80190000  Read-Data   Boiler water temperature: 0.00
17:32:35.675192  BC0192B80  Read-Ack    Boiler water temperature: 43.50
17:32:36.439475  T001B0000  Read-Data   Outside temperature: 0.00
17:32:36.648268  BF01B0000  Unk-DataId  Outside temperature: 0.00
17:32:37.473639  T801C0000  Read-Data   Return water temperature: 0.00
17:32:37.666224  BC01C2780  Read-Ack    Return water temperature: 39.50
17:32:38.470817  T90470014  Write-Data  Control setpoint V/H: 20
17:32:38.509819  R9047000F  Write-Data  Control setpoint V/H: 15
17:32:38.669259  B5047000F  Write-Ack   Control setpoint V/H: 15
17:32:38.710625  A50470014  Write-Ack   Control setpoint V/H: 20
17:32:39.435322  T80000200  Read-Data   Status: 00000010 00000000
17:32:39.632958  B4000020C  Read-Ack    Status: 00000010 00001100
17:32:39.711584  VS: -
17:32:40.434412  T10010A00  Write-Data  Control setpoint: 10.00
17:32:40.638221  BD0010A00  Write-Ack   Control setpoint: 10.00
17:32:41.408558  T100E0000  Write-Data  Maximum relative modulation level: 0.00
17:32:41.600098  BD00E0000  Write-Ack   Maximum relative modulation level: 0.00
17:32:42.422328  T00120000  Read-Data   CH water pressure: 0.00
17:32:42.613193  BC012021A  Read-Ack    CH water pressure: 2.10
17:32:43.400097  T80190000  Read-Data   Boiler water temperature: 0.00
17:32:43.594362  BC0192B80  Read-Ack    Boiler water temperature: 43.50
17:32:44.403977  T001B0000  Read-Data   Outside temperature: 0.00
17:32:44.444649  R00060000  Read-Data   Remote parameter flags: 00000000 00000000
17:32:44.606840  BC0060303  Read-Ack    Remote parameter flags: 00000011 00000011
17:32:44.647002  AF01B0000  Unk-DataId  Outside temperature: 0.00
17:32:45.364705  T801C0000  Read-Data   Return water temperature: 0.00
17:32:45.563885  BC01C2780  Read-Ack    Return water temperature: 39.50
17:32:46.406419  T90470014  Write-Data  Control setpoint V/H: 20
17:32:46.615273  B50470014  Write-Ack   Control setpoint V/H: 20
17:32:47.423628  T80000200  Read-Data   Status: 00000010 00000000
17:32:47.617994  B4000020C  Read-Ack    Status: 00000010 00001100
17:32:48.468681  T10010A00  Write-Data  Control setpoint: 10.00
17:32:48.660176  BD0010A00  Write-Ack   Control setpoint: 10.00
17:32:49.491088  T100E0000  Write-Data  Maximum relative modulation level: 0.00
17:32:49.698838  BD00E0000  Write-Ack   Maximum relative modulation level: 0.00
17:32:50.478115  T00120000  Read-Data   CH water pressure: 0.00
17:32:50.683499  BC012021A  Read-Ack    CH water pressure: 2.10
17:32:51.473938  T80190000  Read-Data   Boiler water temperature: 0.00
17:32:51.671425  BC0192B80  Read-Ack    Boiler water temperature: 43.50
17:32:52.466359  T001B0000  Read-Data   Outside temperature: 0.00
17:32:52.507264  R00300000  Read-Data   DHW setpoint boundaries: 0 0
17:32:52.664749  BC0303C28  Read-Ack    DHW setpoint boundaries: 60 40
17:32:52.705080  AF01B0000  Unk-DataId  Outside temperature: 0.00
17:32:53.443279  T801C0000  Read-Data   Return water temperature: 0.00
17:32:53.644713  BC01C2780  Read-Ack    Return water temperature: 39.50
Schelte
Drchandra
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Posts: 5
Joined: Tue Jun 23, 2020 10:18 pm

Re: Controlling Wolf Ventilation Unit CWL 400

Post by Drchandra »

Thanks, you‘re right! With otmonitor it really works as it should, but in OpenHAB with the OTGW binding not. Obviously there‘s a bug in the binding. I‘ll contact the developer of the binding and I‘ll inform you as soon as I get an answer.

Michael
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