On Wed, 28 May 2008 12:50:05 +0100, Andy Hall
wrote:

On 2008-05-28 10:45:27 +0100, Lobster said:

Andy Hall wrote:
On 2008-05-27 20:46:22 +0100, Mark said:

I have just removed a radiator & noted that a small amount of black
water came out (which later settled out into brown sand-like grains).

The majority of the system is fairly new (all radiators and boiler)
but there is some old pipework. The boiler is a W-B combi (i.e.
sealed). There are no leaks in the system.

I see that there are a huge number of chemical cleaner products and
inhibitors. How can I tell which would be most suitable for my
system?

The first thing is that you need to thorughly flush out the sludge and solids.

There are two reasonable ways to do that:

- Drain system, remove radiators, take them outside and flush them with
a mains hose or pressure washer. Flush water out at each radiator
position.

- Power flush the system. This can be done by paying someone N x
hundred ££s or by renting the equipment and DIYing it.

Not disagreeing that either of the above are the ideal solutions, but
both are reasonably drastic in terms of hassle factor and/or cost.
Given that the majority of the OP's system is pretty new I'd go for
something like Sentinel X400 cleanser, and repeated fill/flush/drain
cycles
http://www.screwfix.com/prods/89458/Plumbing/Central-Heating-Treatment/Sentinel-X400-Central-Heating-Sludge-Remover

followed

by say Sentinel X100 inhibitor:
http://www.screwfix.com/prods/79683/Plumbing/Central-Heating-Treatment/Sentinel-X100-Central-Heating-Scale-Inhibitor-1Ltr

David

The

point was that the system already has quite a bit of particulate
sludge. Cleaner products alone just circulated won't do much with
that. Rather they will end to free up some of the material allowing it
to be circulated into the boiler. That is not wanted.

Therefore some form of mechanical removal is a really good idea.

One could just do the basic Sentinel deal as you suggest and it would
at least prevent further corrosion, but I would be concerned about the
particulate material getting into the boiler and other unwanted places.

Thanks for all the replies. I have looked at hiring a power flusher
but the only one I can find is about £100 and it doesn't mention use
in a sealed system.

Can anyone explain how the fernox or sentinal products are
administered to a sealed system (with out a header tank)?

Fernox and sentinal seem to offer a big variety of products. What is
the difference?