Fernox appear to make AF-10 biocide to deal with this growth - I tried
to buy some but no-one seemed to stock it and I was advised that most
people just add extra inhibitor into the tank to deal with the problem
so I did.
I checked the header-tank yesterday and the growth has returned so I'm
again trying to buy AF-10. The local Plumbase said they could get some
in but I just went to collect it and they'd failed to do so, so now
they're ordering it direct from Fernox. I was again told that no-one
uses it which is why they don't stock it and that it "old hat".
What else could I use or do?
--
dave @ stejonda
UCE Spammer : al...@eagle2005.be.tf : Bots please harvest
Neither brick acid, creosote, nor car body filler are appropriate, so
the answer must be caustic soda :-)
Owain
According to BES' catalogue
FERNOX ALPHI-11. A combined anti-freeze and inhibitor which is suitable
for protecting heating, chilled water, and solar systems. It helps
prevent oxidic corrosion, bacterial contamination and limescale
formation. Suitable for all metals
5 litre £16.43
Thanks for that John I'll add that in if I can't get the AF-10.
The slime is a "bio-film".
See
ehp.niehs.nih.gov/docs/1998/106-12/innovations.html
It probably hasn't got into the main circulation pipework because the
working temperature is too high for it to survive. It has only
proliferated in the stagnant water of the F&E tank, the cold feed and
open vent pipes. The organsims responsible secrete a sticky
carbohydrate coating which protects them from disinfectants and
anti-biotics. Generally, it takes 1,500 times as much disinfectant to
kill and disperse a biofilm as a bacterial infestation; I doubt that
Fernox or household disinfectants will clear the infestation, some
bugs will survive and the bio-film will return in a few months.
It may be Pseudomonas aeruginosa , a very persistent slime that can
clog heating or cooling systems. I'm an engineer, not a
microbiologists, so I'm open to correction by the microbiologists who
frequent this forum. Pseudomonas was in the trade mags a few years
ago, having been identified in a number of clogged-up or contaminated
commercial systems. The organism was getting in through the fill water
and, once clogged, the systems were extraordinarily difficult to
clear. It is present in small numbers in the environment and
(possibly) in the mains water, like legionella. It is harmless in this
form, the problems occur when it is given favourable conditions to
survive and multiply. The recommendation was to disinfect the water
used to fill the systems, to prevent the system becoming contaminated.
I don't know the details, but I think it was low-temperature systems
(water treatment, chilled water, heat recovery), rather than LTHW
heating systems.
Pseudomonas aeruginosa can cause infections, especially lung
infections in cystic fibrosis sufferers, also urinary tract & contact
lense problems.
I think I'd look at converting to a sealed system, if your boiler is
suitable (i.e., it must have a secondary manual-reset high-limit
thermostat), and minimize the lengths of any dead-legs. Check with the
boiler manufacturers. Otherwise do some searching for an effective
biocide. If you've got plastic pipes, then be aware that polybutylene
pipes (e.g., HEP2O) don't like high chlorine levels, chlorine being a
common and effective disinfectant ingredient. I think PEX is OK.
> Pseudomonas aeruginosa can cause infections, especially lung
> infections in cystic fibrosis sufferers, also urinary tract & contact
> lense problems.
good point. I would be a bit cautious about handling it. Bugs in that
quantity could overwhelm anyone's T cells.
Chlorine will evaporate in time, but might do something to reduce slime
and bacteria population for a bit. I'd stick some copper compund in
there, its harmless to your heating system and kills just about
everything. CuSO4 should so it. Swimming pools sometimes use Cu and Ag
in place of Cl2.
Since its not in the hot section, boiling the water for half an hour
would also kill it, fwiw.
A chemical that breaks down the sticky coating may help a lot as well,
by removing most of the defences.
NT
Hmmm, I *will* be more careful.
>
>Chlorine will evaporate in time, but might do something to reduce slime
>and bacteria population for a bit.
Chlorine bleach? But would adding that adversely affect the rest of the
system?
> I'd stick some copper compund in
>there, its harmless to your heating system and kills just about
>everything. CuSO4 should so it. Swimming pools sometimes use Cu and Ag
>in place of Cl2.
I tried to find a source of CuSO4 and failed. Ahhh
http://www.ukpoolstore.co.uk/ does stock both stabilised chlorine
granules & a copper-based 6 Month Algaecide. They're not far from us.
Would either of these be Ok? (Wonders, why is any of this necessary in
my system??? - what is wrong with it?)
>
>Since its not in the hot section, boiling the water for half an hour
>would also kill it, fwiw.
>
>A chemical that breaks down the sticky coating may help a lot as well,
>by removing most of the defences.
>
Hopefully an algaecide will contain that.
Back in t'olden days I can remember getting it in toy shops as refills
for chemistry sets.
I never achieved anything with a chemistry set other than Secret Writing
and a smokey kitchen.
Owain
> I tried to find a source of CuSO4 and failed. Ahhh
> http://www.ukpoolstore.co.uk/ does stock both stabilised chlorine
> granules & a copper-based 6 Month Algaecide. They're not far from us.
> Would either of these be Ok?
It's not an algae, so an algaecide would be of dubious effectiveness.
I'd be very wary of bunging in home-brew chlorine or copper compounds
in the hope of killing it. Thery could create corrosion problems, if
not flushed out. Pseudomonas was resistant to customized biocides, I
wouldn't count on a home-brew toxin. Even if you got the system 100%
sterile, there'll be bugs lurking in the environs of the F&E tank,
ready to recolonize the water when the chemical's effectiveness have
diminished.
The slime isn't in the circulation pipes and isn't causing a problem.
If you must use chemicals, I'd just disconnect, drain and treat the OV,
feed pipe and F&E tank.
I still think a sealed system is the best fix for this. If any bugs get
established in the expansion vessel, they won't get out.
Sorry I don't know more about the appropriate chemicals.
I just did a search of Google Groups and found there is a group called
"bionet . microbiology . biofilms"! I kid you not. Someone there might
have an answer.
yup, and available from both my main news servers. :)
Ah.
>I'd be very wary of bunging in home-brew chlorine or copper compounds
>in the hope of killing it. Thery could create corrosion problems, if
>not flushed out. Pseudomonas was resistant to customized biocides, I
>wouldn't count on a home-brew toxin. Even if you got the system 100%
>sterile, there'll be bugs lurking in the environs of the F&E tank,
>ready to recolonize the water when the chemical's effectiveness have
>diminished.
>
> The slime isn't in the circulation pipes and isn't causing a problem.
>If you must use chemicals, I'd just disconnect, drain and treat the OV,
>feed pipe and F&E tank.
If the Fernox chemicals don't sort it then I'll go this route.
>
>I still think a sealed system is the best fix for this. If any bugs get
>established in the expansion vessel, they won't get out.
I'll keep that idea in reserve for now, but thanks.
I suggest you call the Fernox help line for some definitive advice.
017990550811
The reason why contamination of the feed and expansion cistern has
occurred should be identified and the cause remedied otherwise
contamination will reoccur and the following stages will be a waste of
time.
The system should be drained and thoroughly flushed out.
The header tank thoroughly cleaned manually, ( face mask eye protection
rubber gloves) wipe internal surfaces with a rag soaked in strong bleach
solution.
The tank then should be flushed to remove ALL residual bleach
The system should be thoroughly cleaned out, then disinfected with
biocide ( ask Fernox for their recommendation),
Then again thoroughly flushed, and fully drained
Then and ONLY then should sufficient fresh inhibitor/corrosion proofer
be added.
Yes, time consuming but thoroughness will be rewarded with a trouble
free operation for years to come.
FWIW
Senile chemist