On Wed, 20 Oct 2004 17:03:23 GMT, (Dave£) wrote:


I think it's time I replenished the additives in my system since I
haven't added anything for three or four years, and have added quite a
lot of freshwater during that time, to keep the pessure correct.

What is a good and economical additive to use, and how much for a
smallish 3-bed house?

The crud that I'd most like to eliminate are those hard little black
bits (iron oxide?). I did a desludge job on it about 3 or 4 years ago,
but the black bits are back! - I found some the other day when I
looked inside the secondary heat exchanger..

Thanks

Dave L

The first point is that most corrosion inhibitors tend to lose their
properties after about three years, so it's time to deal with it
anyway.

Second point, is that it is a good idea to put an in-line strainer on
the return to the boiler to prevent particles of crud reaching the
heat exchanger,


There are a few options with inhibitors and dosing techniques:

1) Use a gel cartridge like Fernox Superconcentrate which you inject
via a radiator vent using a mastic gun. Easy, but the most expensive

2) Plumb in a pipe with a service valve to use as a dosing point, then

a) Liquid inhibitor such as Fernox MB-1 can be pumped in against the
pressure using a modified garden sprayer.

b) As a) but release the system pressure and put in inhibitor using a
funnel





..andy

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