On Sun, 21 Dec 2003 19:15:02 -0000, "Terry D"
wrote:



From personal experience, I wouldn't even attempt to remove any of the
radiators. Drain the system at the lowest point - there may also be a drain
valve on the boiler. Switch the boiler off and leave the water supply on to
the header tank, then with all radiator valves open, let it run until clear
(or as clear as possible). Then turn off the mains supply to the header
tank, either by the stop cock or tying up the valve. Let the system drain
fully. Introduce some suitable cleaner (eg Fernox) into the header tank,
close the drain valves, turn on the water supply and allow the system to
fill. Run for a few days, or according to the instructions. Then flush and
drain the system again, then fill with inhibitor (Fernox again possibly).
It shouldn't be necessary to drain the secondary (hot water).

The whole procedure will take you several hours (you will need to bleed all
radiators several times for instance), spread over a few days, but you
shouldn't be deprived of heating for more than a hour or two. My system is
almost 32 years old and still economically provides heating and hot water.
It's even cheaper since I ditched the useless British Gas so-called 'service
contract', whose solution to my last problem (knocking) was to offer me a
new boiler for £2000. Solved the problem myself for less than £30.

Terry D.

This approach will work if the system is not too badly sludged. On
one that is, it won't - I have the tee-shirt from attempting it with a
friend's system which had not been properly looked after.

Despite very thorough flushing and circulating chemical twice, the
radiators were not cleared. The problem is that the path from the
header tank to the drain cock did not go via any radiators so there
was nothing to fluch them through - no exit path either.

In the end, the only way was to take all the radiators outside. They
were loaded with sludge. After that was flushed out, a third dose of
chemical cleaner removed what was left.


..andy

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