Viessmann Vitodens 200w Fluctuating hot water....

[andyathr]

My boiler (and entire central heating system) was installed and first used in August 2009. In February 2011 the hot water began fluctuating hot and cold. The boiler still under warranty was repaired by Viessmann with a new heat exchange plate which was blocked with sludge. They replaced this part under warranty and the system worked correctly again. Until now, when the same fault has re-occurred. They are now saying if they come back and find the same problem , then I will be liable to a call out charge and they would not replace the part under warranty. At no point when they replaced the heat exchange plate in February did they recommend I take any 'preventative actions' (for example, flushing the system). I removed three radiators in the summer to decorate behind and each drained clear to begin with then black toward the end. The system has always had a MagnaClean filter installed. I don't understand why this problem has re-occurred and I am annoyed that the system may require flushing to clear out the debris. Does anyone think the entire system may not have been treated properly when it was installed? Also, if the system were to to flushed, would this clear the problem within the boiler without replacing any parts? I'd really appreciate any professional insight into this before I call the boiler company again.... Thanks

 

[Mbear]

I'm surprised they replaced it the 1st time to be honest. Usually chokages due to dirt won't be covered under a warranty. The part itself isn't faulty, the system is clogging it up

 

[diamondgas]

andyathr - Do you live in a hard water area? Just wondering if it's scale rather than sludge that is effecting your plate hex? It's unusual for a new, sealed and protected heating system to "sludge" up. If your installer cleaned and inhibited your system correctly on installation the production of 'sludge' should be minimal. What's the magnaclean filter like? Is it caked with 'sludge'? Something doesn't sound right to be honest

 

[andyathr]

andyathr - Do you live in a hard water area? Just wondering if it's scale rather than sludge that is effecting your plate hex? It's unusual for a new, sealed and protected heating system to "sludge" up. If your installer cleaned and inhibited your system correctly on installation the production of 'sludge' should be minimal. What's the magnaclean filter like? Is it caked with 'sludge'? Something doesn't sound right to be honest

I live in Edinburgh - soft water. I checked the magnaclean and there was a little but really only minimal 'sludge' around the magnet core. I am trying to get hold of the installer for his views on this too as he is a trained Viessmann installer, but he installed for the developer prior to my purchase of the property...

 

[diamondgas]

What would it cost for a second opinion? You can also investigate the cost of sending off a water sample to the likes of Sentinel for testing. The results would tell you whether the water is as Viessmann are saying or not! I'd be pretty livid if after 2 years I was told that it was down to "sludge" on a sealed system! Has any of your neighbours had similar problems? Usually on a development there are trends regards sytem faults..

 

[andyathr]

It's a relatively small development of only 7 flats and I have emailed everyone to investigate any other issues. Thank you for the suggestion of 'water analysis'

Andrew