Magnaclean failed me, boiler got blocked so what's next?

The Viessmann 100s combis I've seen have all suffered from a black material inside the (presumably) rubber flexibles inside the boiler.

We mainly fitted the heat only 100s which haven't got this problem.

I don't know what the material is that forms on the inside of the hoses (making them 'crusty') but when that gets in the plate it is goodnight vienna.
 
simond said:
The Viessmann 100s combis I've seen have all suffered from a black material inside the (presumably) rubber flexibles inside the boiler.

We mainly fitted the heat only 100s which haven't got this problem.

I don't know what the material is that forms on the inside of the hoses (making them 'crusty') but when that gets in the plate it is goodnight vienna.
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Sorry to resurect this old thread but @simond did you ever figure out what is the black crusty stuff in the inside of the hoses of the Viessmanns 100?
I have one of these and those flakes are causing hell. Are they magnetite? Would a magnetic filter on the return help?
 
My Viessmann problems started after a service. Hoses not replaced but found tons of flakes in plate exchanger and in heating water.
Is this a common issue on the Viessmanns? Mine is 5y old.
I'm thinking those circulating flakes are causing pump noise, blockages and restricted flow...
UFH pipes are quite thin too enough for those things to cause a problem.
Looking to have the hoses replaced, system flushed, maybe install a strainer somehow?
 
The flakes are coming from the hoses breaking down so a strainer wouldn't really help
 
muggles said:
The flakes are coming from the hoses breaking down so a strainer wouldn't really help
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I'd ask the Viessmann tech to have the boiler and UFH loops drained and the hoses replaced and then flushed with fresh water then maybe add inhibitor but apparently Viessmann doesn't recommend inhibitors. Don't have any rads.

Would a filter not be necessary after to pick up any remaining flakes stuck or would the flushing take them out... power flushing necessary on UFH pipes?
 
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Gasguru said:
Same in Germany and the US...

https://forum.heatinghelp.com/discussion/186183/viessmann-rubber-hose-problems

Every manufacturer that has gone down the rubber hose route have the same issues...from older Vokeras, older Vaillants to Viessmann.
Vaillant offered a replacement copper pipe kit (at huge expense).
Hoses attract debris and unless your systems spotless it's bad news.
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My post as well there to get some more ideas, however I had also found quite a few vids about this issue.
What's shocking to me is that I had 3 "authorized by Viessmann" from the official Viessmann service provider list people over and NONE of them mentioned anything about this. But they did replace the plate HE, the pump, did lots of per hr trouble shooting and flushing. I luckily came across this thread which sparked my interest in the issue.
For Viessmann main tech support said calcified main HE, and blamed dirty 'water' which is astonishing to me because at the same time they don't recommend inhibitors for the main reason of their rubber hoses!
 
They like to perpetuate the myth that over in Germany they don't use inhibitors and their boilers are running sweet....google translate and their heating forums will tell you otherwise.
 
Gasguru said:
They like to perpetuate the myth that over in Germany they don't use inhibitors and their boilers are running sweet....google translate and their heating forums will tell you otherwise.
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The amount of issues on that Viessmann Community forum is something else. I'm sure they sell a lot of boilers so normally they will have eventually a large absolute number of issues.
 
Every boiler has poor design issues. But this hose is really easy to remove and clean at service. I always make sure i don't squeeze it before i have got the bottom connection off. I have quite a few that i service but only a couple have the problem with the hoses and both of these systems have high levels of iron oxide in them. the ones with very clean systems and inhibitored are no trouble
 
snb said:
these systems have high levels of iron oxide in them. the ones with very clean systems and inhibitored are no trouble
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Is it the combustion or the oxygen in the water reacting with the parts/stainless steel that causes this in a closed system?
We do not have any radiators, just underfloor heating plastic pipes, copper pipes for flow/return and I figure the manifold is brass.

PS. @snb there's a hose at the back as well which is only accessible by removing the entire large heat exchanger!
 
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