Vaillant ecoTEC exclusiv 146/4-7 - F55 CO problem

[pvydra]

Grüße an einander.
Ich kann nicht so gut deutsch, entschuldigen Sie Bitte den Text in Englisch:

I am in a quite desperate situation with my Vaillant ecoTEC exclusiv 146/4-7 boiler.

Long story short:

Boiler works in emergency mode, producing a terrible amount of CO (out of range of analyzers, ~20.000ppm) and no one is able to find out what is wrong.

Long story:

Cca in February this year I have noticed that the boiler makes some loud noise, like vibrations or shaking (

)
On screen was emergency mode S40/F55, CO sensor is broken. I called a (first) technician.
He replaced the CO sensor but the problem remained. Then he came with a suspicion that it could be a problem with chimney.
The chimney is cca 3m going from boiler directly to the roof, with a coaxial pipeline for exhaust and air inlet.
If the chimney would be disconnected, it could cause such a CO problem.

So I called chimney-sweep, he checked the chimney (with endoscopic camera) and chimney is absolutely tight and alright.

I called another boiler-technician and he gradually, step by step checked gas pressure (correct), replaced a gas valve and finally replaced system board.
None of these helped.

Technician admitted that this boiler series is quite unusual in Czechia, and he has almost none experiences with it.
He also contacted Czech Vaillant support but they were not able to help us as well.

P.

 

[Hausdoc]

Let the expert carry out an annular gap measurement.
Even after 10 minutes, no CO² may be present in the combustion air.
About an endoscopic examination can not find the error.

 

[Wolfhaus]

Boiler works in emergency mode, producing a terrible amount of CO (out of range of analyzers, ~20.000ppm) and no one is able to find out what is wrong.

Der Kessel arbeitet im Notfallmodus und produziert eine schreckliche Menge CO (außerhalb des Bereichs der Analysegeräte, ~ 20.000 ppm), und niemand kann herausfinden, was falsch ist.

Achtung hier besteht Lebensgefahr. Benutzen Sie das Gerät nicht.

Attention here is danger to life. Do not use the device.