Viessmann rubber hoses problem

[dr911t]

Are the rubber hoses known to fail on the 2016-2019 Viessmann Vitodens 100W?
I've been dealing with circulation issues inside the boiler and I've found some anecdotal reports online of "crunchy hose syndrome" aka black granules or flakes.
Some photos of the issue from several youtube vids showing the issue.

Viessmann auth service tech wants to replace the entire heat exchanger on a 5 year old boiler due to 'limescale' and restricted flow.... Shady. I don't have rads, only underfloor heating. The rubber hose in the back is annoying to replace as the whole heat exchange has to be removed on the 100W. I found out about this on my own as three heating service companies already have looked at the boiler and didn't even mention this as a possibility despite having found flakes in the heating water and in the plate heat exchanger.

Any suggestion of the best method to get rid of these?

• drain entire heating system and boiler
• change hoses
• flush boiler and UFH loops with mains water
• maybe install a filter on the return to catch other remaining flakes still circulating - don't think they are magnetic - simple Y filter or a Fernox TF1 Omega?
• add inhibitor

 

[ShaunCorbs]

Yes normally change them on a yearly service

Don’t crunch them in the boiler

 

[dr911t]

Yes normally change them on a yearly service

Don’t crunch them in the boiler

Ever run into some so soiled in a Viessmann that they caused issues for circulation, pump, noise in a way that the symptoms were similar to a clogged heat exchanger?

 

[ShaunCorbs]

Yes as it restricts the flow out of the main hex

 

[townfanjon]

To clean and flush the hoses , clean plate is a easy quick job. Hoses were in short supply a couple of months ago .

 

[dr911t]

Thanks for the help gents!

The service guys ran a pressure pump with some chemical connected to the flow and the return on the boiler only but never replaced the hoses. I guess that wouldn't be enough to completely get rid of these flakes from the hoses and an actual replacement is needed? It almost feels like that made the boiler run worse...

Do you reckon we need to power-flush the floor heating pipes to get these flakes out if they made their way or would they be just free floating around and mains tap pressure would be enough to get them out?

 

[ShaunCorbs]

Nope need to replace the hoses

 

[cjg]

changed a few but on older boiler than yours. you should have fitted a filter really.

 

[dr911t]

changed a few but on older boiler than yours. you should have fitted a filter really.

Not sure they are magnetic. Didn't test them. Will a magnetite filter catch these?

 

[cjg]

most filters will catch debri

 

[dr911t]

Thinking to install a Spirotech Spirotrap.