Vaillant Ecotec plus 831 Combi - Vibrating Noise from DHW

[Clem63]

Hi, looking for some help/ideas re the above boiler which I installed last summer. Called out by the customer today, when DHW is drawn off the boiler starts to make a vibrating sound which seems to be coming from the combustion chamber area, not the plate heat exchanger area. Noise only occurs when under full load, reduce water temp to say 50c and all quiet, when supplying just the central heating similarly all quiet. Takes around 20 seconds for the noise to build up after a hot tap is opened. Full pressure flush undertaken on install and magnaclean fitted too. Is in a hard water area but wouldnt expect problems within 6 months. Pressures all look good. Searched the forums and cant see any similar reports. Any ideas would be appreciated, thanks

Simon

 

[harold5]

sounds like the main HE.

 

[Clem63]

Well all i can up with is to flush the system again as does seem to suggest a restriction in the main heat exchanger but strikes me as odd for such a new system, power flushed and protected via a magnaclean. also dont get the time delay for the vibration to kick in or why only on DHW....

 

[harold5]

it does it on hw because of the extra heat input. make sure your waters clean and pass it back to vaillant under warranty.

 

[gas4you]

System muck sitting in the bottom of the main HE coils.

Needs isolating from the haeting system and reverse flushing/draining of the HE until all muck removed.

I would doubt it is covered under a warranty call out. They will probably blame bad installation, not good enough flushing.

 

[harold5]

they will change it no problem, even with a system full of crap they might test the water first ,tell you to flush it and then fit a new one. they do round my way anyway.

 

[gmgas]

hey got the same prob can anyone advise, can it be slight blockage in main heat ex cos it is exactly the same prob as described ,if that is prob whats the best way to shift it i was thinking turn off all the rads bar one put kamco on the one removed so just goes through boiler see if there is any debri or any other ways using sent jetflo chemical

 

[simond]

Have you done a combustion analysis?

 

[gmgas]

hey
thanks for answering Not done combustion but please tell me more am in need of purchasing an anyliser an getting the training b4 deadline next year have arranged service call but an keen to discover the prob as have quite a few of these fitted and never had this prob am i missing something apart from an anyliser is it co2 ratio out an if so can anyone enlighten me as to why this would make this noise when on full rate can it be adjusted or is the burner finished is only 13months old and was powerflushed by me using sentinal an Kamco when fitted in march 2010 any answers would be gratefull an may be inspired to buy anylyser.
ta for any help on this also how is business have found thius year really tuff so far this year only fitted 9 boilers this year an done a bit of maintanance

 

[simond]

Business is cr*p thanks.

Whilst the boiler could be sludged up, I would agree with you this is unlikely because of the time preparing the job.

If the CO2 ratio is out the boiler can be more noisy.

Are your flue seals OK? There is a weakness on some of these.

Without combustion analysis equipment I would find it very difficult to work on condensing boilers. Went to a Worcester Ri the other day, chucking out 6000ppm CO. Looked fine, if I had no analyser I wouldn't have expected anything amiss. I'd suggest you get one now, business is bad for them too, might get a good deal. The TPi one is quite good.

 

[dreadnoughtheating]

Simond beat me to it, I had flue seals condemned by Vaiilant (Homeserve actually.....) on a not ever so long 'horizontal' run. Condensate ran down from flue turret onto fan causing a heck of a vibration.

Had to cannibalise some flue spares I had in stock, was told by Vaillant Techies they are not available as separate items, but, the guys in the CC, reckon they are.....

DH

 

[gmgas]

cheers guys appreciate the advice am going to get an anyliser on monday cant do the job without one by the looks of it but thanks for the tips good luck an hope we all stay busy

 

[dreadnoughtheating]

Have a word with Kev at GES (hemel Hempstead?) http://www.gesuk.com/home.html

he is an acknowledged expert on FGA's.

FWIW i have the Anton Sprint V2, with gas leak detector, temp clamps & Printer etc, would not be able to trade effectively without it....

DH

 

[gmgas]

hey fellas more news on the ecotec noise
The Vaillant engineer condemed the installation adviseing my customer it was at risk and not to use it
nice of him that
this is because the standard flue kit which i fitted had not been drilled and screwed together didnt know any thing about that i have allways fitted the clamps to the appliance and the flue nice and tight have never seen one come loose ever this is a standard flue going out of the rear and pointed in on the out side with the little round rubber ring to finish it off.
i couldn move it unless was doing it on purpose.
any how the co was adjusted to 9.2% an hey presto no noise now he has also taken water sample and even though noise is gone still wants to fit new main heat exchanger and wants it power flushed again nice all this.
have never heard thias before re the flue would be interested to know how many standard flue kits have been drilled and screwed ifeel i have been take care all gmgas

 

[Agile]

At least if nothing else this has persuaded the OP that a gas analyser is required for boiler installations.

It surprises me that the regulations dont actually require one when passing the assessment on them is!

Drilling and screwing the flue is part of the requirement to ensure the flue joints dont move.

If you have correctly mortared the flue to the wall then I dont see why you then fit the rubber gasket. When I see that it makes me thing that its a cowboy installation that has not been mortared!