vaillant combi 824 rubber connection tube blocked

[gasburt]

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This rubber tube is located on the return from the main heat exchanger it was nearly totaly filled with metal deposits (from a badly flushed system maybe) I was just wondering what caused the problem and why the muck built up at this place ,My idea was that the rubber tube built up some static charge ,this would then attract small metal filings to stick to the inside of the tube these would then rust and attract more debris ,the replacement rubber tube has a white strip down it maybe a different rubber compound .
ps if this rubber tube is removed make sure the muck does not fall down the inside of the copper pipe as this will cause the same problem somewhere else in the system .

 

[Deleted member 105431]

quite common for dirt to collect in these tubes due to the vibration absorbion in them. The new white stripe denotes an improved construction and compound used, even better would be the copper pipe conversion kit as fitted to new production models. Fit a spirovent on the return and flush the system with x800 and it'll be good as new.