ism7mqtt with Wolf CHA heat pump

[imautohuttraeger]

This is the follow up of an off-topic discussion with @Ragdag in another thread.

viewtopic.php?p=336185#p336185

So let me outsource it to this separate topic. I am looking for a solution for a simple user like me to get data from my Wolf CHA07 heatpump via the communication module ISM7i. I notify hereafter my answers to questions, that @Ragdag already asked me:

Which Wolf network modules do you have: Link Home, ISM7i, ISM8i, or none?
-> ISM7i

Which CHA do you have (07 or 10), with or without cooling, and are there other Wolf parts connected (BM-2 control module, mixer modules, solar, ventilation)?
--> CHA07 with BM-2 control display module

Which values would you most like to see in Domoticz?
--> actual power, consumed energy, amount of heat produced, number of cycles (compressor starts).

Which Domoticz version are you running?
--> currently 2026.4 (build 18479) beta or latest beta

When you tried ism7mqtt, do you remember where it got stuck?
--> Not really, it is more than one year ago. There where error messages in Linux (Raspi) even before I could get further.

Do you already have an MQTT broker running (for example Mosquitto)?
--> Yes, Mosquito is running and receiving data, for example via MQTT auto discovery

What does your Raspberry Pi show when you run this command in a terminal? That tells me which version you need.

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uname -m

--> armv7l

Is Docker installed on it? (No problem if not.)
--> No, Docker is not installed.

Do you use the Wolf Smartset app regularly, or could you live without it?
--> I use it regularly and I don't need to control the heat pump via Domoticz. My installing company is also using it for remote maintenance if necessary.

Do you know the password of the ISM7i?
--> Yes, I have the password.

[Ragdag]

This is the follow up of an off-topic discussion with @Ragdag in another thread.

viewtopic.php?p=336185#p336185

So let me outsource it to this separate topic. I am looking for a solution for a simple user like me to get data from my Wolf CHA07 heatpump via the communication module ISM7i. I notify hereafter my answers to questions, that @Ragdag already asked me:

Which Wolf network modules do you have: Link Home, ISM7i, ISM8i, or none?
-> ISM7i

Which CHA do you have (07 or 10), with or without cooling, and are there other Wolf parts connected (BM-2 control module, mixer modules, solar, ventilation)?
--> CHA07 with BM-2 control display module

Which values would you most like to see in Domoticz?
--> actual power, consumed energy, amount of heat produced, number of cycles (compressor starts).

Which Domoticz version are you running?
--> currently 2026.4 (build 18479) beta or latest beta

When you tried ism7mqtt, do you remember where it got stuck?
--> Not really, it is more than one year ago. There where error messages in Linux (Raspi) even before I could get further.

Do you already have an MQTT broker running (for example Mosquitto)?
--> Yes, Mosquito is running and receiving data, for example via MQTT auto discovery

What does your Raspberry Pi show when you run this command in a terminal? That tells me which version you need.

Code: Select all

uname -m

--> armv7l

Is Docker installed on it? (No problem if not.)
--> No, Docker is not installed.

Do you use the Wolf Smartset app regularly, or could you live without it?
--> I use it regularly and I don't need to control the heat pump via Domoticz. My installing company is also using it for remote maintenance if necessary.

Do you know the password of the ISM7i?
--> Yes, I have the password.

Thanks for the complete overview, that helps a lot. One of your answers is important, so let me start with that.

The catch: the ISM7i accepts only one direct connection
The ism7mqtt documentation says the ISM7i accepts only one connection at a time, so while ism7mqtt is running, the Smartset app cannot connect directly to the module. That is a limit of the ISM7i itself, not of ism7mqtt, so a Domoticz plugin would run into exactly the same thing.

What I could not find out is whether the Smartset app via the Wolf cloud keeps working, both for you away from home and for your installer's remote maintenance. That goes through the internet instead of directly to the module, so it might be unaffected, but nobody documents it. For you that is the deciding question.

Your old error messages
There is a known problem with ism7mqtt on newer Raspberry Pi OS versions: the connection to the ISM7i fails with an SSL error right at the start. There is a fix for it (a small change to a settings file), so that may well be what stopped you last time. For your Raspberry Pi (armv7l) there is a ready-made version, so nothing needs to be built.

A possible next step
The only way to answer the cloud question is to try it: run ism7mqtt for a short while, check in the Smartset app over mobile data (Wi-Fi off) whether you still get in, then stop ism7mqtt again. Stopping it puts everything back as it was. If the cloud keeps working, ism7mqtt can stay running and we can connect it to Domoticz. If it does not, this route is not an option for you, and I would rather know that before you spend an evening on it.

Also good to know: other users report that changes can sometimes arrive a few minutes late, so this is fine for power, energy and starts, but not for second-by-second monitoring.

If you want to give it a try, I'd like to get the preparation right in one go so we don't have to go back and forth too much. Could you run the commands below on the Raspberry Pi and post the complete output? They only read information and change nothing.

Replace 192.168.1.50 on the first line with the IP address of your ISM7i:

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ISM7=192.168.1.50
cat /etc/os-release
uname -m
getconf LONG_BIT
ldd --version | head -n 1
openssl version
ldconfig -p | grep -E "libicu|libssl"
free -h
df -h ~
ping -c 3 $ISM7
for p in 9092 9091; do timeout 3 bash -c "</dev/tcp/$ISM7/$p" 2>/dev/null && echo "port $p open" || echo "port $p closed"; done

And a few questions:

1. Do Domoticz and Mosquitto both run on this same Raspberry Pi? If not, what runs where?
2. Does Mosquitto need a username and password? (Just yes or no, please don't post the password.)
3. In Domoticz, open your MQTT Auto Discovery hardware: what is filled in as the "Auto Discovery Prefix"?
4. Does the ISM7i always get the same IP address (fixed in your router), or can it change?

With that I can write the steps for your exact setup.

[imautohuttraeger]

I am on a one week holiday now until next weekend. But via VPN I could at least access my Pi on the tablet. This is the output:

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PRETTY_NAME="Raspbian GNU/Linux 13 (trixie)"
NAME="Raspbian GNU/Linux"
VERSION_ID="13"
VERSION="13 (trixie)"
VERSION_CODENAME=trixie
DEBIAN_VERSION_FULL=13.2
ID=raspbian
ID_LIKE=debian
HOME_URL="http://www.raspbian.org/"
SUPPORT_URL="http://www.raspbian.org/RaspbianForums"
BUG_REPORT_URL="http://www.raspbian.org/RaspbianBugs"
armv7l
32
ldd (Debian GLIBC 2.41-12+rpt1+deb13u1) 2.41
OpenSSL 3.5.4 30 Sep 2025 (Library: OpenSSL 3.5.4 30 Sep 2025)
        libssl3.so (libc6,hard-float) => /lib/arm-linux-gnueabihf/libssl3.so
        libssl.so.3 (libc6,hard-float) => /lib/arm-linux-gnueabihf/libssl.so.3
        libicuuc.so.76 (libc6,hard-float) => /lib/arm-linux-gnueabihf/libicuuc.so.76
        libicutu.so.76 (libc6,hard-float) => /lib/arm-linux-gnueabihf/libicutu.so.76
        libicutest.so.76 (libc6,hard-float) => /lib/arm-linux-gnueabihf/libicutest.so.76
        libicui18n.so.76 (libc6,hard-float) => /lib/arm-linux-gnueabihf/libicui18n.so.76
        libicuio.so.76 (libc6,hard-float) => /lib/arm-linux-gnueabihf/libicuio.so.76
        libicudata.so.76 (libc6,hard-float) => /lib/arm-linux-gnueabihf/libicudata.so.76
               total        used        free      shared  buff/cache   available
Mem:           921Mi       310Mi       203Mi        13Mi       476Mi       610Mi
Swap:          920Mi       130Mi       790Mi
Filesystem      Size  Used Avail Use% Mounted on
/dev/mmcblk0p2   59G   14G   43G  24% /
PING 192.168.1.119 (192.168.1.119) 56(84) bytes of data.
64 bytes from 192.168.1.119: icmp_seq=1 ttl=64 time=2.65 ms
64 bytes from 192.168.1.119: icmp_seq=2 ttl=64 time=1.82 ms
64 bytes from 192.168.1.119: icmp_seq=3 ttl=64 time=1.48 ms
--- 192.168.1.119 ping statistics ---
3 packets transmitted, 3 received, 0% packet loss, time 2004ms
rtt min/avg/max/mdev = 1.475/1.981/2.646/0.490 ms
port 9092 open
port 9091 closed

Do Domoticz and Mosquitto both run on this same Raspberry Pi?
--> Yes

Does Mosquitto need a username and password?
--> Yes

In Domoticz, open your MQTT Auto Discovery hardware: what is filled in as the "Auto Discovery Prefix"?
--> Default string: "homeassistant"

Does the ISM7i always get the same IP address (fixed in your router), or can it change?
--> Fixed in the router and with cable LAN (not WiFi)

[Ragdag]

I am on a one week holiday now until next weekend. But via VPN I could at least access my Pi on the tablet. This is the output:

Code: Select all

PRETTY_NAME="Raspbian GNU/Linux 13 (trixie)"
NAME="Raspbian GNU/Linux"
VERSION_ID="13"
VERSION="13 (trixie)"
VERSION_CODENAME=trixie
DEBIAN_VERSION_FULL=13.2
ID=raspbian
ID_LIKE=debian
HOME_URL="http://www.raspbian.org/"
SUPPORT_URL="http://www.raspbian.org/RaspbianForums"
BUG_REPORT_URL="http://www.raspbian.org/RaspbianBugs"
armv7l
32
ldd (Debian GLIBC 2.41-12+rpt1+deb13u1) 2.41
OpenSSL 3.5.4 30 Sep 2025 (Library: OpenSSL 3.5.4 30 Sep 2025)
        libssl3.so (libc6,hard-float) => /lib/arm-linux-gnueabihf/libssl3.so
        libssl.so.3 (libc6,hard-float) => /lib/arm-linux-gnueabihf/libssl.so.3
        libicuuc.so.76 (libc6,hard-float) => /lib/arm-linux-gnueabihf/libicuuc.so.76
        libicutu.so.76 (libc6,hard-float) => /lib/arm-linux-gnueabihf/libicutu.so.76
        libicutest.so.76 (libc6,hard-float) => /lib/arm-linux-gnueabihf/libicutest.so.76
        libicui18n.so.76 (libc6,hard-float) => /lib/arm-linux-gnueabihf/libicui18n.so.76
        libicuio.so.76 (libc6,hard-float) => /lib/arm-linux-gnueabihf/libicuio.so.76
        libicudata.so.76 (libc6,hard-float) => /lib/arm-linux-gnueabihf/libicudata.so.76
               total        used        free      shared  buff/cache   available
Mem:           921Mi       310Mi       203Mi        13Mi       476Mi       610Mi
Swap:          920Mi       130Mi       790Mi
Filesystem      Size  Used Avail Use% Mounted on
/dev/mmcblk0p2   59G   14G   43G  24% /
PING 192.168.1.119 (192.168.1.119) 56(84) bytes of data.
64 bytes from 192.168.1.119: icmp_seq=1 ttl=64 time=2.65 ms
64 bytes from 192.168.1.119: icmp_seq=2 ttl=64 time=1.82 ms
64 bytes from 192.168.1.119: icmp_seq=3 ttl=64 time=1.48 ms
--- 192.168.1.119 ping statistics ---
3 packets transmitted, 3 received, 0% packet loss, time 2004ms
rtt min/avg/max/mdev = 1.475/1.981/2.646/0.490 ms
port 9092 open
port 9091 closed

Do Domoticz and Mosquitto both run on this same Raspberry Pi?
--> Yes

Does Mosquitto need a username and password?
--> Yes

In Domoticz, open your MQTT Auto Discovery hardware: what is filled in as the "Auto Discovery Prefix"?
--> Default string: "homeassistant"

Does the ISM7i always get the same IP address (fixed in your router), or can it change?
--> Fixed in the router and with cable LAN (not WiFi)

Before you start: we (Me and Claude) did our best to check everything below against the ism7mqtt source code and documentation, but I don't have a Wolf heat pump, so none of this has been tested on a real one. No guarantees, so please read each step before you run it.

Thanks, that is everything I needed. Your Pi looks like a good fit: Debian 13 is supported by the software ism7mqtt is built on, the required libraries are installed, the ISM7i is reachable on the port that current firmware uses, and the Domoticz prefix matches what ism7mqtt uses. No rush with any of this, enjoy your holiday first.

A correction
I mentioned an SSL problem and a fix for it last time. That turns out to be outdated: since 2024 ism7mqtt makes its own secure connection to the ISM7i, so that error should not happen anymore. You don't need to change any settings files.

What this test does and doesn't do

• It checks whether the Smartset app still works through the Wolf cloud while ism7mqtt is connected to the ISM7i.
• It checks whether the heat pump values arrive in Mosquitto.
• It does not change anything on the heat pump: ism7mqtt only reads.
• It does not create anything in Domoticz yet.

Step 1: download ism7mqtt
Copy and paste this block into the terminal:

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sudo apt install -y wget unzip mosquitto-clients
mkdir -p ~/ism7 && cd ~/ism7
wget https://github.com/zivillian/ism7mqtt/releases/download/v0.0.22/ism7config-linux-arm.zip
wget https://github.com/zivillian/ism7mqtt/releases/download/v0.0.22/ism7mqtt-linux-arm.zip
unzip -o -d config ism7config-linux-arm.zip
unzip -o -d mqtt ism7mqtt-linux-arm.zip
chmod +x config/ism7config mqtt/ism7mqtt

Step 2: read your setup from the ISM7i
This creates a file called parameter.json with the list of values your installation has. The second line asks for your ISM7i password; nothing is shown while you type, that is normal. Press Enter when done. The tool itself shows nothing when it works, so give it up to a minute.

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export ISM7_IP=192.168.1.119
read -rsp "ISM7 password: " ISM7_PASSWORD; echo; export ISM7_PASSWORD
cd ~/ism7/mqtt
../config/ism7config
cat parameter.json

Please post the output of the last command. It only contains numbers (which devices and values exist), no passwords or addresses, so it's safe to share.

Step 3: start ism7mqtt for the test
Replace YOUR_MQTT_USER with your Mosquitto username. It asks for the ISM7i password and the Mosquitto password, again without showing them. Both programs run in the background, so they keep running when you disconnect the VPN.

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cd ~/ism7/mqtt
export ISM7_IP=192.168.1.119
export ISM7_MQTTHOST=127.0.0.1
export ISM7_MQTTUSERNAME=YOUR_MQTT_USER
read -rsp "ISM7 password: " ISM7_PASSWORD; echo; export ISM7_PASSWORD
read -rsp "MQTT password: " ISM7_MQTTPASSWORD; echo; export ISM7_MQTTPASSWORD
nohup mosquitto_sub -h 127.0.0.1 -u "$ISM7_MQTTUSERNAME" -P "$ISM7_MQTTPASSWORD" -t 'Wolf/#' -v > mqtt.log 2>&1 &
sleep 2
nohup ./ism7mqtt > ism7mqtt.log 2>&1 &

Step 4: test the Smartset app
Wait about 5 minutes, so ism7mqtt has time to connect and read everything. Then turn the VPN off on your phone or tablet (otherwise the app might reach the ISM7i through your home network, which would spoil the test), open the Smartset app and check whether you still see your heat pump and its current values.

Step 5: look at the results and stop the test
Turn the VPN back on, log in to the Pi again and run:

Code: Select all

cd ~/ism7/mqtt
cat ism7mqtt.log
wc -l mqtt.log
head -n 5 mqtt.log
pkill -x ism7mqtt
pkill -x mosquitto_sub

The last two lines stop both programs, which puts everything back as it was.

Please let me know:

1. The output of cat parameter.json from step 2.
2. Did the Smartset app still work while ism7mqtt was running?
3. The output of step 5. ism7mqtt.log will be short, which is normal. mqtt.log shows the heat pump values as they arrive in Mosquitto, which tells me how to connect them to Domoticz. Please glance over it before posting, and leave out anything you don't want to share.

Please use the commands exactly as above. ism7mqtt has a debug option that prints your password, so don't add any extra options.

When you are back home, there is one more test for later: whether the Smartset app still works at home while ism7mqtt runs. At home the app may try to connect to the ISM7i directly, and that is the connection ism7mqtt occupies.

[imautohuttraeger]

Great! This is really kind of you and will finally enable me to get what I wanted. Thank you very much!

I think that the Wolf smartset app only connects to the cloud. At least it works from any internet connection. But the Wolf cloud server connects to the heat pump of course.

As I am on holiday until next weekend, I will try it out in a week and will report here.

[imautohuttraeger]

I am back in the saddle and proceeded everything according to your instructions. However, as I am back home, I have access to the Pi without VPN, so I ignored everything related to the VPN. But I tested the connection of the Wolf-Smartset App both with my home WiFi and with only mobile cell phone connection. In both cases, it works without any problems. Also the web access in a browser is working (www.wolf-smartset.com).

I have attached two text-files for the outputs.

I am really excited to the next steps!