Vaillant ecoTEC pure automatic modulation and SetMode

[pawelmuszynski]

Hello,

I have Vaillant ecoTEC pure VC 226/7-2. It's detected as a MF=Vaillant;ID=BAI00;SW=0709;HW=1303. Configuration loaded: "vaillant/bai.308523.inc", "vaillant/08.bai.csv"
I'd like to emulate a room controller (like VRC700, etc.). I read that it sends SetMode command every 10 minutes and I checked when I stop sending SetMode, settings will be reseted after 20 minutes. According to john30/ebusd#179 (comment) I created SetModeOverride to have ability to send proper message. It turns out when I send "0;60.0;45.0;-;0;0;0;0;0;0" value my gas boiler keeps water at 60 degrees but the automatic modulation doesn't work. It works at minimal power (25%). When I send "-;60.0;45.0;-;0;0;0;0;0;0" value, ebus controller is not in use (d.90 register shows 'off') and automatic modulation starts working fine but the boiler doesn't use the values and set the water temperature to 55 (it's also showed in d.05 register) It looks like it's a default value when you stop sending SetMode (SetModeOverride). It's set manually in the boiler. Can someone show me what values of SetMode are sent by room controller? Or how to enable automatic modulation during sending SetModeOverride?

EDIT: Even if I set it to "0;-;-;-;0;0;0;0;0;0" ModulationTempDesired is suddenly decreased to 25%.

[wizu]

#220

[pawelmuszynski]

Hello,

based on #170 (comment) I redefined the record for SetModeOverride to:

wi,BAI,SetModeOverride,Betriebsart,,08,B510,00,hcmode,,UCH,,,,flowtempdesired,,D1C,,,,hwctempdesired,,D1C,,,,hwcflowtempdesired,,UCH,,,,setmode1,,UCH,,,,disablehc,,BI0,,,,disablehwctapping,,BI1,,,,disablehwcload,,BI2,,,,setmode2,,UCH,,,,remoteControlHcPump,,BI0,,,,releaseBackup,,BI1,,,,releaseCooling,,BI2

I also redefined the invocation to:

#!/bin/sh

hcmode="0"
flowtempdesired="65"
hwctempdesired="45"
hwcflowtempdesired="-"
disablehc="0"
disablehwcload="0"

ebusctl w -c bai SetModeOverride "$hcmode;$flowtempdesired;$hwctempdesired;$hwcflowtempdesired;-;$disablehc;0;$disablehwcload;-;0;0;0"

and the boiler has started increasing its power after several minutes:

$ ebusctl read -V ModulationTempDesired
bai ModulationTempDesired =57.7 % [Modulationssollwert]

I will check during the winter how long it take the water to heat up. I have old charts to compare. Now it's too hot outside to turn heaters on for longer time.

Thank you @wizu to guide me to the right topic.

[HiQual]

Hello @pawelmuszynski
Many thanks for your "SetModeOverride" settings - I can now write my "FlowTempDesired" and modulation remains working.
I tried to write "PartloadHcKW" by changing the third field in the SetModeOverride command, to set the bai maximum output power - so far without success.
If you have any suggestions I would be very pleased to hear them - thank you.

[pawelmuszynski]

Hello @HiQual
The 3rd value from SetModeOverride is hwctempdesired. It's responsible for the target temperature in your hot water tank. For max power setting I set it manually in the boiler. I can see that writing to PartloadHcKW and PartloadHwcKW registers don't change the max boiler power. I just tested it on hot water tank heating. I didn't dive into it because manual setting is enough for me.

Answering to my previous question it looks like my change on SetModeOverride works fine with modulation.

[HiQual]

Hello @pawelmuszynski
Many thanks for your reply. I am doing the same as you - and it is working well.
Just in case anyone else is reading this, I should explain that my question meant to say I had altered the bai.nnnnn.inc file SetModeOverride line by replacing hwctempdesired with PartloadHcKW - without success. And like you I found that trying to write PartloadHcKW individually does not work.

[dulek]

@pawelmuszynski: Hey, I'm trying to get this working, but I found out that using SetModeOverride I can only lower the desired temperatures compared to the values set on the boiler display. I can't get them higher.

I could set the high values on the boiler and keep a loop of messages lowering them constantly, but for the sake of possible ebusd or Home Assistant breakage I'd rather have the boiler reset down, not up.

Had you observed a similar effect? Or maybe I'm running the boiler in a wrong mode?

[bobrippling]

Sadly I've found the same, I can only lower.

I was thinking with john30/ebusd-esp#89 that if we could get the ebus device to continuously keep the temperature low (which is what I believe Tado and other products do) then we'd have a way to deal with it, but with the device firmware being closed source we can't really do much

[dulek]

Ha, thanks for confirming. I enabled my heating curve simulation with the heater default set to a high desired temperature value and so far it runs pretty good, but surely there are multiple things that can break. So far I've set up alerts to notify me when anything is out of the ordinary and let's see.

[dulek]

And for anyone looking for this, as I spent quite some time finding this, here's the formula to calculate Vaillant heating curves: https://protonsforbreakfast.wordpress.com/2024/10/18/vaillant-heat-pump-controls-part-3-formulas-and-spreadsheet/

[ghosalmartin]

I have a glowworm 35c, but it presents with the same hw/sw codes as you guys.

I for the life of my cannot find the SetModeOverride

I just get a element not found.

Do I need to add it manually to the definitions?