Zehnder ComfoAir CA350 integration via serial connection (RS232) and MQTT

[adorobis]

Yes, with automations in Home Assistant you can also control the ventilation level. If you are new to HA start with reading the following section in documentation:

Automating Home Assistant

One comment though, I don’t think that you can continue using the auto mode as it is controlled by the Comfo Control or another Zehnder controller. Once switching over to HA you need to replace all the controls there. For sure with this integration there is no auto mode for the climate entity:

[christian_by (Christian)]

Hi, I setup all the connections but I couldn’t install python3 because I am using HassOS on my Raspberry. I am quite a beginner in the linux world. Is it possible to just copy the scripts into the python_scripts folder within HassOS? Or is there any way without install all new? Thx

[bremby]

Hi, you can follow this procedure

Zehnder ComfoAir CA350 integration via serial connection (RS232) and MQTT

Hello, As this was my first custom integration in HA, i’ve written the different steps which i have followed, and some explanations (based of course on the previous posts + documentation). If it’s too much “beginner oriented” don’t hesitate to tell me, i can remove this post, otherwise i hope i can help some other beginners like me. Don’t hesitate if a modification is required. As a prerequesite, you need to have a MQTT broker installed in your HA. Architechture First of all, a quick overvie…

[adorobis]

As far as I know you can’t install any service on HassOS. Someone would need to make an add-on for it… You can install it on a dedicated RPi or ESP8266 module.

[christian_by (Christian)]

Thanks. In this case I think I don’t implement it Makes it too much complicated just for this one device.

[Dapolux]

Hi @adorobis,

With the better weather that we have now in France, the summer by pass valve (which should be binary_sensor.ca350_bypass_valve), is switching on (i could verify it with my previous domotic solution, + that extraction temperatures check), but the sensor stays being “off”.

1. I’m i the only one to have this issue?

Moreover, even if maybe the question is not “home assistant relevevant”, the valve is switching on, even is the temperature is under the defined temperature (20°C by default).

2. Do you know which is the “logic” which switches the valve?

Have a nice day.

[adorobis]

1. Could be that the logic is opposite. Not clearly mentioned in the documentation - it is reading the Byte[4]:
   

   

2. Not entirely clear but the temperature has to stay above or below for some time (days?) before the “operationg mode” switches from Winter to Summer and oposite.

As I can’t have both the factory controller and RS232 connected at the same time I actually don’t know what the unit is doing. Is the bypass actually open or closed? Can you tell? You have to either open it or check with the original controller.

[Dapolux]

Thanks for the reply.
At this time the with todays weather, its again off (in real + in the sensor, which is correct):

I will continue tracking it and let share the results.

[Dapolux]

So today, weather is warmer, i can see that the bypass seems to be on (see temperatures), but the sensors doesn’t show it:

[adorobis]

It works ok(ish) with mine:

For sure switching from Winter to Summer is taking some time but not sure what is exactly the logic (a few days need to be warm enough to make the switch).
Regarding the bypass valve - not sure about this one when exactly it opens and if the current logic in the integration reads it correctly. Does 0% mean open or close? I’ve changed the comfort temp to below internal and external ones and it still stays ‘off’ despite being in the ‘summer’ mode.

So I’m really not sure what is the logic of the bypass valve - maybe someone know?

[adorobis]

@adorobis

So I’m really not sure what is the logic of the bypass valve - maybe someone know?

Well, google is my friend, not the first time. Aparently there is an article that somewhat explains it but not to the level of details to fully understand the logic:

Insights | Summer Bypass

“How does it work?
A modulating summer bypass maximises comfort to
the nth degree by allowing the bypass to be open,
closed or somewhere inbetween depending on how
much heat recovery is required.
Guided by an optimum comfort temperature which
looks at both temperature and humidity
Uses an intelligent algorithm to look at both internal
and external conditions
Adds a further layer of intelligence with historical
data as our perception of comfort is often based on
previous conditions
Provide ‘cold recovery’ as further contribution to
improve comfort levels in summer months”

So in short there is some algorithm that controls it and we can only to some extent influence it by setting up the “comfort” temperature.
And from some other document:

You could understand that bypass would never open when the unit is in winter mode.

[Dapolux]

Thanks alot @adorobis, it’s more clear for me on how it works.
Viewing your screenshots, i’ve checked deeper, and i’ve identified that i dont have any “sensor” for the bypass, i just have the “binary_sensor”, i probably messed something.

I then checked with mqtt explorer if the values are returned by the fan, and in fact mqtt seems to be correctly published as i can see the correct values:

So i guess i should have an issue on the integration part.

[adorobis]

Seems that the script is not publishing the two topics:

comfoair/ca350_summer_mode
comfoair/ca350_bypass_valve

check your config.ini file and enable the auto discovery feature, probly service restart will be required:

HAEnableAutoDiscoverySensors=True

Also make sure you have the latest version of the script.

[Dapolux]

So i have reinstalled all from git (+restart the raspberry + restart HA), and HAEnableAutoDiscoverySensors=True is already set, and i’m still not having the sensor (only the binary sensor)
Just to be sure, when you speak on “config.ini”, you mean the file “ca350” right?

[adorobis]

no, config has been moved to a separate file now, sample file is in the repo config.ini.dist, copy it to same directory as the ca350 file (as config.ini) and adjust entries in it. If you enable all 3 HA autodiscovery params you should see the following topics in MQTT:

[breinonline]

I’m currently looking for a way to add my Zehnder Q600 to my Home Assistant setup. Any change this integration would work?

And do I understand correctly you really need to from RJ45 > RS232 then RS232 > USB otherwise it won’t work?

[adorobis]

From what I know the Q series is not using RS232 anymore but a modbus or something similar. There is built in integration for HA but requires a lan module for the Q model:

Zehnder ComfoAir Q

Alternatively you can also get KNX interface module, but it is more expensive and if you don’t have KNX at home you’ll need an IP - KNX gateway/router and power supply which will make it overall 2-3 times more expensive than the LAN module for comfoair.

[breinonline]

Thank you, that’s a clear answer. The lan module is also quite expensive. I will try to find a cheap store then

[adorobis]

After a few warmer days the bypass is getting opened and is properly reflected in HA. Does it work for you now?

[Dapolux]

Thanks for asking, but not for the moment :).
In fact i think i’m missing something with this new config.ini file.

I have copied it in the ca350/bin directory, renamed as “config.ini”, adapted it with my data (server/user/pass/ set true to autodiscover), restarted the raspberry pi, restarted HA, and nothing new appeared as a bypass sensor.

Looking at the documentation in your github, i dont see also this sensor, am i missing something else?

Exposure to mqtt seems ok:

but no more bypass sensors found: