THZ / LWZ Tecalor Stiebel Eltron Heizung

[lwzler]

@lwzler: I have version 4.09 which is the second oldest tested here and it required a delay of 100-200 ms. I use a 3 m long USB cable. If nothing helps with the crashs you might, for test purposes, try a shorter USB cable.

Maybe something got mixed up here. I am not running into any problems with this configuration. For me everything works very nicely with no crashes at all.
I postet my config as for "Jakl" the USB connection was discussed as a pssible problem.

For me the LWZ<->Raspi combination seems to be very robust against USB problems, as my configuration is way out of the norm (max. 3m length for USB cables).

[willybauss]

One question reagarding passive cooling: In order for this to be efficient (in-house-circulation) I need to turn off the normal ventilation, right?

No, not at all. First of all you should have a look into the installation manual, where it's described in deep detail.
Basically as soon as you switch the passive cooling to anything <> 0 one of both ventilation fans is switched off, the other one runs at increased power level. Now you should open at least one window, so that in- or output ventilation can happen through the open window. This works as a bypass for the heat exchanger, so that you can really get cool air into the house at night, which is no more heated up while passing through the heat exchanger.
Advantage against the "Sommerkassette" (which replaces the heat exchanger by a simple bypass) is, that you're still able to ventilate the house during day time (when it's hot outside), and the heat exchanger keeps the cold inside. Using a "Sommerkassette" instead would mean you have to switch off the ventilation completely during hot day time, to avoid heating up the inside.

[Heiner]

Hi,

never heard of sommerkasette. You mean when it is hot I just chnage the Programm times for the Fan, from some day hours into night hours, correct?

[immi]

Dear all
it is right, we have to find a nice concept for summer.

I was thinking to the following:
Leave window open (tilted) in the basement and

30 minutes drawing the air from the 2 bathrooms and kitchen: this cools down fast 70% of the house (exeption of the bedrooms).
30 minutes blowing the air to the bedrooms.

this can be achieved easily without programming: just switch "p75passiveCooling" from 1 to 2 every 30 min....
theoretically.

maybe you have better suggestions.
immi

[houseowner123]

Code Auswählen Erweitern

12.1.1 Passivkühlung
Die Passivkühlungwird freigegeben, wenn die Außentemperatur mindestens 2 Stunden lang 3 K über der Raumsolltemperatur liegt. Sinkt dann die Außentemperatur um 3 K unter die Raumsolltemperatur wird die Passivkühlung aktiviert: Steht ,,PASSIVKÜHUNG"auf
1, wird der Zuluftlüfter abgeschaltet und die Leistung des Abluftlüfters um 20 %erhöht. Dadurch wird über die geöffneten Fenster kühle Außenluft in Wohnung gesaugt.
Bekommt,,PASSIVKÜHLUNG" den Wert 2, wird der Abluftlüfter ab - geschaltet und die Leistung des Zuluftlüfters um 20 % erhöht. Hier müssen Sie die Fenster nicht öffnen. Diese Variante ist allerdings weniger effektiv und funktioniert nicht bei sehr dichten Häusern (d.h. wenn beim Blower-Door-Test die Luftaustauschzahl n50 <= 1 ist. Spätestens um 10 Uhr morgens wird die Passivkühlung beendet.
12.1.2 Passivkühlung über Fortluft
Bei der ,,PASSIVKÜHLUNG ÜBER FORTLUFT" [MENÜ/LÜFTUNG] wird die Luft über ein Klappensystem direkt aus dem Keller gesogen. Die
Klappen können über den Ausgang x 18-2 (,,Lüftung Nacht") angesteuert werden. Die Freigabekriterien sind dieselben wie bei der
Passivkühlung.

This is straight from the manual. Thanks, willy!
So Passive cooling stage 2 is no option for most of us because of our BDT values. So, what immu suggests as alternative is Passikühlung über Fortluft? What is the advantage of passive cooling stage 1? The difference between Abluft and Fortluft is not clear to me. It seems that passive cooling is already temperature- and time regulated. Wouldn't FHEM then just mess with those LWZ/THZ internals?

I have a Sommerkassette, it can be ordered from Tecalor, cost about 80 €. In terms of cooling the house down at night I do not find it effective. Only after a 5 K difference between in- and outside temp you get a 1K lower temp in the morning. In tropical nights (min temp 20°C) it not effective anymore and you open all your windows anyway and move into the cool but moist basement.

Thanks,
Tom

[Gassi]

Did anybody install http://www.tecalor.de/dam/downloads/produkte/lueftungssysteme/THZ-303-403-SOL/172090-37758-8875_THZ_303-403_de/bedienung---installation-luftungsgerat-thz-303-403-sol.pdf "15.2.4 Anschluss Außenluft Wohnungslüftung optional" on page 61?
Or can anyone explain the funktion.

[houseowner123]

Did anybody install http://www.tecalor.de/dam/downloads/produkte/lueftungssysteme/THZ-303-403-SOL/172090-37758-8875_THZ_303-403_de/bedienung---installation-luftungsgerat-thz-303-403-sol.pdf "15.2.4 Anschluss Außenluft Wohnungslüftung optional" on page 61?
Or can anyone explain the funktion.

Interesting. Never seen this before. Either if you do not want use the ventilation system at all or to provide a spacial alternative to the main inlet.

[willybauss]

Hi,

never heard of sommerkasette. You mean when it is hot I just chnage the Programm times for the Fan, from some day hours into night hours, correct?

no, not at all. Please check the manual first.

[willybauss]

this can be achieved easily without programming: just switch "p75passiveCooling" from 1 to 2 every 30 min....
theoretically.

My experience shows that 30 minutes is MUCH too less to have any effect, even in a wooden house. In a house made from stone it's even worse. We should talk about multiple hours instead.
Using mode 2 you can open the windows as well of course. But in this case the fresh air goes through the whole ventilation pipe system before it comes into the target room, and during this - possibly long - travel it already heats up a lot.

[willybauss]

What is the advantage of passive cooling stage 1?

fresh air comes directly from the outside, without any detour through the piping system, which would heat the fresh air up before it reaches the room.

The difference between Abluft and Fortluft is not clear to me.

Forget about the "Fortluft" alternative. I discussed it with a support gui. It's not worth to be mentioned at all. Mode 1 and 2 are the only useable options.

It seems that passive cooling is already temperature- and time regulated. Wouldn't FHEM then just mess with those LWZ/THZ internals?

Exactly. The THZ's own logic will prohibit any "misuse". To work around it you would need to switch the fans manually (or by "low level" fhem switching commands) on/off and to specifig power levels. Sounds dangerous: as soon as fhem gets out of order you're lost.

I have a Sommerkassette, it can be ordered from Tecalor, cost about 80 €. In terms of cooling the house down at night I do not find it effective. Only after a 5 K difference between in- and outside temp you get a 1K lower temp in the morning. In tropical nights (min temp 20°C) it not effective anymore and you open all your windows anyway and move into the cool but moist basement.

That's what I expected, and the reason to not install it.

[immi]

My experience shows that 30 minutes is MUCH too less to have any effect, even in a wooden house. In a house made from stone it's even worse. We should talk about multiple hours instead.
Using mode 2 you can open the windows as well of course. But in this case the fresh air goes through the whole ventilation pipe system before it comes into the target room, and during this - possibly long - travel it already heats up a lot.

I think we have a comunication problem Willy: my suggestion was to toggle from mode 1 to mode 2 every 30 min.
this means during the night you have 4hours  mode 1 and 4hours mode 2
immi

[houseowner123]

Immi,

But in passive mode 2, in high efficency houses like ours, that are wrapped in PVC (our BDT is 0.8...), you would reach a steady-state pretty fast and no air would move in. You would only wear out the ventilators.
Can somebody enlighten me what the Passivkühlung with Fortluft actually does and does it have to do with a basement as described in the manual?
Tom

[immi]

Hi Tom
as written before
Leave window open (tilted) in the basement and
30 minutes drawing the air from the 2 bathrooms and kitchen: this cools down fast 70% of the house (exeption of the bedrooms).
30 minutes blowing the air to the bedrooms.

toggle from mode 1 to mode 2 every 30 min.
this means during the night you have 4hours  mode 1 and 4hours mode 2
The duty cycle could be optimized.

With mode 1 you cool down through the window tilted in the basement and get fresh air from the basement.
with mode 2 you mix up air in all room wich are not in the path.

immi

[micomat]

next week the weather forecast is up to 28°C so i will test the first time the passive cooling
thanks to immi who made it possible to switch it from the iPhone 

[willybauss]

I think we have a comunication problem Willy: my suggestion was to toggle from mode 1 to mode 2 every 30 min.
this means during the night you have 4hours  mode 1 and 4hours mode 2
immi

You're right. Last summer I used mode 1 the whole night. The open windows were in bedroom and living room, so (since almost the whole ground floor is one great room consisting of living room, dining room and kitchen) almost the whole house got fresh air directly from the outside through the open windows. I believe that's more efficient than togggeling between mod 1 and 2, since the flow doesn't need to be turned into other direction frequently.

Drawback of my solution is: as soon as I need to close the window in bedroom (since it's too loud outside for any reason) there's no more any fresh air in bedroom at all. I would need to switch to mode 2 manually when closing the window. Therefore my next big project in FHEM will be to check all my window sensors (I installed hidden ones, made from reed contacts and magnets during the construction phase of the house) by fhem and switch between mode 1 and 2 automatically based on the result.