Evil growth in hot water header tank

Ian

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Apr 25, 2010, 9:01:58 AM4/25/10

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Four years ago we had a new central heating boiler installed in the
airing cupboard upstairs. It is an icos HE24 condensing boiler, open
vent. Apart from the electronic controller failing a year ago,
everything has been fine. No problems of any kind.

A few weeks ago we had a radiator replaced. When draining down the
system, the plumber discovered an evil growth in the boiler
feed/expansion tank in the loft. The growth was a dark brown, gungy,
jellyfish-like mass about dinner plate size and about one inch thick. He
removed the tank from the loft, disposed of the gunge, and thoroughly
cleaned the tank before replacing it back in the loft and adding
inhibitor.

Since then, there has been a strong, damp, "metallic" smell in the
boiler/airing cupboard, which appears whenever the boiler is firing.
When the boiler is switched off for a few hours, the smell goes away
There is no trace of the smell in the loft around the header tank.

There is no sign of any leaks around the new radiator or anywhere else.
As a double check, the plumber has just re-examined the header tank, and
reports that a new evil growth (a thick yellow skin on top of the water)
has appeared.

Is the water temperature too low perhaps, to kill off the evil bacteria?
(I don't know what the temperature setting is, but it hasn't been
altered since the original installation, and the new rad was a straight
replacement for an old one).

Could there be a problem if the new inhibitor was not the same type as
the old?

We're stumped. Any ideas on what to do next? I

--
Ian

S Viemeister

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Apr 25, 2010, 9:29:07 AM4/25/10

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Sounds like this stuff -

<http://en.wikipedia.org/wiki/Iron_bacteria>
<http://www.hhs.state.ne.us/enh/IronSulfurBacteria.pdf>

If it is, raising the temperature should help get rid of it.

Adrian C

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Apr 25, 2010, 9:33:21 AM4/25/10

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On 25/04/2010 14:29, S Viemeister wrote:

> Sounds like this stuff -
>
> <http://en.wikipedia.org/wiki/Iron_bacteria>
> <http://www.hhs.state.ne.us/enh/IronSulfurBacteria.pdf>
>
> If it is, raising the temperature should help get rid of it.

Sort of like the foundary scene at the end of the Terminator movies ;-)

--
Adrian C

The Medway Handyman

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Apr 25, 2010, 10:58:37 AM4/25/10

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Ian wrote:

> We're stumped. Any ideas on what to do next?

Run! Run away while you still can!

--
Dave - The Medway Handyman
www.medwayhandyman.co.uk

cynic

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Apr 25, 2010, 3:05:38 PM4/25/10

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> If it is, raising the temperature should help get rid of it.- Hide quoted text -
>
> - Show quoted text -

The last thing you do is raise the temperature of the water in the
plastic header tank!

Put some biocide in the water to stop the growth.

The smell in the boiler compartment is probably down to whatever
inhibitor your guy used and some may have leaked out of the AAV on the
boiler.

BTW I believe the ICOS uses an aluminium heat exchanger - he did use
an aluminium compatible inhibitor didn't he?

Grimly Curmudgeon

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Apr 26, 2010, 7:58:49 AM4/26/10

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We were somewhere around Barstow, on the edge of the desert, when the
drugs began to take hold. I remember "The Medway Handyman"
<davi...@no-spam-blueyonder.co.uk> saying something like:

>Ian wrote:
>
>> We're stumped. Any ideas on what to do next?
>
>Run! Run away while you still can!

I recall reading "Slime", about a genetic freak growth that developed in
the New York sewers. Charming stuff that tended to grab people on the
bog.
Luckily, it was fiction.

The Medway Handyman

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Apr 26, 2010, 6:42:03 PM4/26/10

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Sure about that? If I were the OP I'd be running...

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