Integrating HVAC system to HA via BMS interface

21

:partying_face: +1 very interetsed in hearing how this goes too.

Also have a Vent Axia Sentinel Kinetic. Would love to be able to bring it into my growing HA-base home hub. Have also considered using an energy meter to infer what boost level it is on, as I yea I don’t think you can read info out of the system via the BMS interface from what I’ve read previously, but this looks like a good approach too. Other option would be to consider something like GitHub - aelias-eu/vent-axia-remote: Vent-Axia wired remote protocol but that is likely a lot more effort in the short term

22

Hi there, thanks for that link. It does indeed look like a lot of effort to use the RS232 but I love your idea of basically measuring the electrical load on the motor. I think I have a spare Shelly 2pm laying around so I might try it.
At the moment I’m waiting for Sonoff 4CH Pro to arrive. I’m planning to flash it with ESPHome and use to control the SW1, SW2, SW3 and SW5.
I’m also using Shelly UNI to measure water temperature in a tank nearby the Vent-axia unit and it has a spare analog input. I’m going to wire it to the HVAC to measure voltage on the LED connection and convert it in HA to a boolean value to indicate FAULT status.

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23

Hey… so I’ve got a Shelly Plus 1 PM wired into mine, so I can see power usage, and yup there is a spike when the fan boost is running, but am not doing anything yet about controlling this rather than just feeding a sensor in HA.

Screenshot 2022-05-05 at 12.39.42

Did you get to make any progress on this with the Sonoff? I’d be interested in hearing options on how to control the fan speed…

24

Hi there, I decided to give up on the idea of measuring fan speed - I don’t really need it. Eventually, I might add some simple power consumption meter to it but for now, I have other things in the pipeline.

My HVAC unit is located very close to the hot water tank. I’ve been using three temperature probes wired to Shelly Unit to measure water temperature in the tank. I have decided that since the Shelly Uni also has two potential-free outputs and one analog input so I might as well use them.

I have wired the digital outputs to the HVAC SW3 and SW5 to control the Boost function as well as the emergency fire shutdown function. I also wired the LED output to the analog input on the Shelly and converted it to a binary value in Home Assistant so that way it tells me if the unit has any error or maintenance message :slight_smile:

So to summarize, the HVAC is normally running in automatic mode, controlling the RPM depending on sensed temperatures and humidity levels but I can override it with a manual boost. If a fire alarm activates in the house, Home Assistant will deactivate the HVAC to reduce oxygen supply.

I’m satisfied with the way it works, at least for now, so my next little project now is to get my newly installed smart electricity meter to report usage to Home Assistant and I’m also playing with some ESP controllers and ESPHome which I’m beginning to like very much :slight_smile: .

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25

Looks like you are using the Shelly Uni to do multiple things… interesting.
Do you mind sharing a drawing on how exactly you wire the Shelly Uni?

26

Hi Guys,

I don’t understand what I’m doing wrong:

It doesn’t matter what switch I shunt (= shorting +/- per switch?), they all give me the same result: Activating boost mode…

What am I missing?

Thanks for the help & great guide above!

27

Hi MonYvel,

Which control mode have you enabled? You can see that on the screen during boot sequence.

Could you post a photo of your wiring?

28

Thanks for your reply. I don’ see it mention anything about Control mode during boot. Following steps show during boot:

start boot

  1. Sentinel Kinetic: V17/03
  2. Language: Dutch (I’m translating here :))
  3. Airflow: %
  4. Wireless controll: Not installed
  5. Humidity sensor: Installed
  6. Norm. airflow: 30%
    Boot finished

I don’t have any wiring in place yet (apart from the 4 power cables to the right.) My J4 jumper is on the same location as yours, 3-4

At this moment I’m just manually shorting SW+/- ports before buying a Shelly uni or something else.

Thanks for the help!!

IMG_6867|690x184

29

Ok, in my device selecting the correct Control Mode is crucial so I’m guessing that maybe this is why it doesn’t work on your model. Possibly your device alao has two control modes but there is a different method of switching between them. Possibly inside the Commissioning Menu.

I would need to look into the manual for your particular model. Could you check what exact model you have?

30

Hi @PapaSierra82,

Thanks again. My exact model is a 443935 Kinetic Plus B.

Unfortunately I can’t find any info or manual online for this exact model, because in all manuals I find online they mention the Control Mode 2 setting.

However, in my manual I have on paper (and in Dutch) they never mention the Control Mode 2 setting. As far as I can understand. For my Switches 1-5 to have different functions, I need this: Kinetic Vent Wise Controller | Vent-Axia
Vent Axia Sentinel Kinetic Vent-Wise Control Module PCB 441780 (A655) 5015135417802 | eBay

This module is, according to my manual, attached to the J4 connection & gives the switches different functions. If this part is not connected, all switches have the same function: Boost.

I’ve photographed the part of the manual where this is explained, unfortunately it is in Dutch

Edit: I’ve translated the part marked in red (see photo manual)

“ When connected to J4, a voltage-free contact is activated for

Sensor signal between the connections + and -

When connecting Vent-Wise PCB to J4, the Vent-Wise sensor signal is activated

Do not attach standard sensors or voltageless switching contacts in this mode.”

Now, It is not the end of the world if only the boost mode is “working” I was only interested in this one anyway (Boost when taking a shower, …) But the other functions are nice to have. :slight_smile:

Would a Shelly One Plus be sufficient for me to accomplish this? (Main reason for this one is I will not need an extra power supply, can just attach it to the 230v of the HVAC unit itself.

Thanks again for all the help!

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31

Ok, this is a bit strange and disappointing if there’s no control mode 2 on the unit. I have a contact inside Vent Axia support, someone who helped me with my integration and he was very knowledgeable. I sent him and email and hopefully I will get a response on Tuesday (they are closed this Monday). He was fast replying to me last time.

I will try to help more but I think now it’s best to wait for the reply as there might be an easy fix to this problem if we only have more information on the system.

Have a good weekend

32

Actually, can I ask you what would you like to interface ideally? What I have on my unit at the moment is a control of the boost, full shut down of the fan (linked through HA to fire system) and I also read a voltage from the LED contacts and convert into boolean in HA to give me maintanance/fault alerts.

I might integrate more in the future but this is good for now. I’m using Shelly Uni which works fine but TBH if I was doing it second time, I would use ESP chip flashed with esphome, powered by a tiny AC-DC converted from Aliexpress and enclosed in a 3d printed case. That’s what I use now for nearly all my automations and I love it for it’s simplicity and powerful customization it gives.

33

Apologies for the late reply, apparently you are limited to three replies short after the other as a new user.

I was hoping to have the same functionality as you, BOOST, Shut off & Led read out. But if only boost is possible that’s fine by me to.

I’m very new to the home automation stuff apart from the “ready made” Phillip Hue’s & Tado’s. And don’t have a home assistant running yet, was planning to use the Shelly cloud to start with & move to home assistant & ESP flash later on.

The Shelly One Plus interested me more because of the possibility to power it on 230v, no other reason.

Thanks again for al the help!

34

I’m not sure why Shelly 1, I think shelly Uni would be better for the job. That’s what I’m using and it does the job fine with the potential-free outputs controlling boost and fan shut-off functions and the analog input connected to the LED output.

If you decide on the Uni, you will also have an option to connect up to 3 temperature probes (Stainless Steel Package Waterproof Ds18b20 Temperature Probe Temperature Sensor 18b20 - Sensors - AliExpress) which you can use to monitor air temperature in the air ducts (which is what I will do if I find spare few minutes).

Shelly products are great to start with. I highly recommend you start with HA as soon as you can as that is where the magic really happens. You can suddenly manage and automate so many systems, all from one place.

In relation to ESP and powering microcontrollers from 230V, this is what I use:

3.3V 700ma is good for most ESP chips with basic sensors connected. Some soldering skills are required.

Aliexpress is really great for this kind of stuff. That’s where I get 80% of my home automation and 3d printing hardware.

Reply from Vent-Axia:
> Thank you for your email.
> The original Sentinel Kinetic units did not have control mode 2, it only had one control mode.
> Is this a very old unit?

When did you have it installed?

35

Hi @PapaSierra82,

Thank again for the great reply. I will read in to the stuff you mentioned. Thanks.

About the Vent-axia unit: it was installed in 2012. So yea, not very modern.

Only boost is fine for me, the other features are nice to have :sweat_smile:

Thanks again.

36

I’ve got a Vent Axia Sentinel Kinetic Advance S
I found a cheap and simple way to control it via HA without the need for BMS interface.

Buy the Volt-Free Expansion board image
Get an ESP8266 and set it up with 4 relays controlled through ESPHome (there are loads of online guides and circuit diagrams - Example ESP8266 Relay Module – Control AC Appliances (Web Server) : 14 Steps - Instructables
Then wire each relay to the 4 extra volt free terminals

In my pictures you can see I linked 2 pairs of relay boards, this was because I got duff information initially so I can confirm 4 relays are needed.

The ESP Home code I used is as follows:

captive_portal:

dallas:
  - pin: GPIO2
# Individual sensors
sensor:
  - platform: dallas
    address: 0xab3c01f0958ca128
    name: "Loft Temperature"

switch:
  - platform: gpio
    name: "MhevBoost"
    pin: 14
  - platform: gpio
    name: "MhevPurge"
    pin: 12
  - platform: gpio
    name: "MhevLow"
    pin: 05
  - platform: gpio
    name: "MhevNormal"
    pin: 04

Then go into commissioning mode on the Vent Axia and pick SW2, SW3, SW4 and SW5 setting each one to whatever mode you choose. I decided on Purge, Boost, Normal and Low.

Note in my code there is a Dallas sensor (I added an external sensor to monitor the loft temperature but you don’t have to)

I now have Zigbee sensors in 3 rooms (Kitchen, Toilet and Bathroom) which link to a sonoff zigbee stick and with the help of HA they put the Vent Axia into Purge Mode.

Also 4 automations monitor the position of each switch shown in HA and when one is turned on it ensures the other 3 are turned off so that the mode is never confused.

Volt Free Board installed

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My relay unit inside an electrical box
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The final complete installation of my controller with the Vent Axia unit behind… no comments on the cowboy install of the vent axia please which I have spent some time correcting thanks to a poor installer (not vent axia)
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37

Thanks for sharing. I never knew you can get an expansion card like this and it’s pretty inexpensive too.

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38

I have a Sentinel Kinetic in my office. I’ve managed to (almost) accurately control the fan speed. All I did was connecting a 0…10V controller to the P1 connectors. Thank you for the essential info I’ve found on this thread.

In the settings I’ve changed:

  • boost speed to 100%
  • normal speed to 25% (which was the default)
  • P1 settings to “Pure 0-10V” (Humidity also works, if you set the min to 25% and max to 100%)

I’ve remembered 0-10v is used in light dimming so there are tons of controllers on the market. I wanted something that works on my Zigbee network so I don’t have to add another controller to the wifi. Turns out, Philips Hue do make a controller under the “Modular” brand but that’s impossible to buy.

Quick search on eBay (or aliexpress) and there’re many. I’ve picked one named " ZigBee 3.0 LED Light Dimmer Controller AC100-270V 0-10V 1-10VSmart Home APP for Smartthings Tuya Hub Echo Plus Alexa Control".

I’ve paired it with my Hue bridge from where I can control the brightness.

  • Brightness between 0 and 50% brightness goes proportional from 25% to 50% fan speed.
  • Brightness from 50% up are mapped one to one to fan speed (so 75% brightness = 75% fan speed).
  • Turn off: it goes back to normal speed (25% in my case)

Dunno why it changes from 50% onwards but it’s fine for me. Total cost around 15-20€/£/$

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39

This is a great discussion, thanks for the details all! I just took delivery of a vent axia sentinel kinetic and want to smarten it up and connect to HA.

My question to you guys @ptuk @PapaSierra82 is do you think it’s better to use the proportional voltage for total control of fan speeds, or just switch the modes via dry contracts.

I’m leaning towards the latter, because once the MVHR is set up with good low, normal, boost and purge settings it’ll be easier to manage its state… but maybe I’m missing something?

I’m also thinking maybe a Sonoff 4CHPRO flashed with ESPhome to do the dry contact switching, then a separate Shelly and/or ESP to monitor power usage and the 4 duct temperature + humidity to properly track its performance. This way there isn’t one device trying to do it all.

Any thoughts on the “ideal” setup?

40

I’ve opted for 0…10V because that gives you more control over what the fan is actually doing. The unit can be a bit noisy from 80% upwards so having that fine-grain control could be beneficial. I didn’t want to control 3 separate relays so that was easily sorted by using the proportional input.

Both methods work at the end of the day :blush: