The unit was installed in September 2021 and worked without any issues till November last year.
On November 18.11.2022 the right side of the unit (that is where the extract 'Abluft' and supply 'Zuluft' is) was flooded with condensate and the right ventilator was broken.
The serviceman representing the Viessmann distributor that installed the unit upon examination concluded the following:
1) temperature sensor on the pre-heater appears to be in line with the specification
2) the pre-heater itself appears to be working properly
3) the insulation of the air pipes with the extract air ABLUFT and supply air ZULUFT seems to be sufficient and appriopriate
4) the pre-heater device does not seem to turn on at temperatures below -5 degrees Celcius
For the above reasons a decision was made to replace the controller board Reglerleiterplatte 7868418 and the internal wiring kit Interner Verdrahtungssatz 7868440 as well as to repair the Ventilator (or replace it with a new one when not possible to repair it).
The new components arrived last week and all has been installed, HOWEVER, the condensate is still appearing on the right side of the device with temperatures close to 0 degrees Celsius at night.
Unfortunately, I have no idea what could be done next and why the condensate keeps on appearing after replacing the components to new ones. I was told it should not be there, but unfortunately it is.
Can you please help?
Thank you in advance.
Best regards
Wojciech
