its the installers responsibility to make sure the system he fits the boiler to is clean, if its dirty he hasnt fulfilled his responsibilities.
I would however be interested to hear the noise to know its not a combustion noise as the 415 and 418 have been known to whistle with the CO2 set at the higher end of tolerance, but I would have expected the Vaillant engineer to know that.
Where abouts are you? I may know who the vaillant engineer who visited.
I would however be interested to hear the noise to know its not a combustion noise as the 415 and 418 have been known to whistle with the CO2 set at the higher end of tolerance, but I would have expected the Vaillant engineer to know that.
Where abouts are you? I may know who the vaillant engineer who visited.