Tim+ wrote:
We have a pressurised HW system (an Albion Ultrasteel cylinder) with a
external 18L expansion vessel.

For some time now we've suffered from intermittant dirty water supplies
which we suspect was due to a problem with our water mains further down
the street (as manifest by the major blowout recently
http://i1052.photobucket.com/albums/...k/da49f87f.jpg )

Anyhow, our water supply (or at least our cold water supply) has cleared
up but we continue to intermitently get dirt in our HW supply which I've
been putting down to a HW cyclinder full of silt. If no water has been
drawn for a while (like overnight) the HW is visibly stained.

Today I thought I'd try and drain down the HW tank using the drain cock
to see what the water was like nearer the bottom of the tank (expecting
it to be really dirty). I filled half a bucket and poured it into our
sink and this is what it looked like
http://i1052.photobucket.com/albums/...EDFA1D3991.jpg
As you can see, only very lightly stained.

It seemed a bit pointless to carry on draining the tank so I
repressurised and and refilled the sink from the tap with this result.
http://i1052.photobucket.com/albums/...ED925ED3B6.jpg



What I want to know is, where the feck is all this crud hiding?? This
always happens if I depressurise and repressurise the tank. It's had a
new pressure vessel about 3 weeks ago after the diaphragm failed in the
old one so I know it's not the pressure vessel that's full of crud.

As I say, our cold supply seems okay but I'd really like to flush all
this crud out of our HW system but I'm mystified why water drained from
the bottom of the tank is so much cleaner than what's coming out the top.

Tim

I think the answer is this.

(i) switch of all heat input
(ii) leave the hot taps all on full for as long as it takes. The
constant water flow should in the end stir up the silt enough to get it
all out.
(iii) any silt left is probably too heavy to ever come out again so who
cares?


--
Ineptocracy

(in-ep-toc-ra-cy) €“ a system of government where the least capable to
lead are elected by the least capable of producing, and where the
members of society least likely to sustain themselves or succeed, are
rewarded with goods and services paid for by the confiscated wealth of a
diminishing number of producers.