On Sun, 28 Jan 2007 00:08:02 +0000, Siggy wrote:

Ed Sirett wrote:


Acid descaling is surprisingly popular especially considering that
limescale is rarely the principal problem with a heating system.

It isn't really the limescale I want rid of, as much as the black stuff.
I have had a persistent pressure loss for some time now and I'm buggered
if I can find it. Hence I have had to frequently top up the system with
more fresh (oxygenated) water via the filling loop. Being a lazy
*******, I haven't been quite as diligent about refreshing the
anti-corrosion inhibitor, so I keep clogging up my DHW heat exchanger.
I have just swapped it out with my handy spare for the 4th time now, and
it's getting to be a pain in the derriere as this occasion is only 3
months on from the last swap out! I figure that my combi main heat
exchanger also has collected much of the muck, and to cut a loooong
story short, I just want to clean the whole fecking lot out once and for
all and shove some anti-leak chemical in (which I have also obtained)
before another fresh dose of corrosion inhibitor.....

What are the symptoms you are trying to tackle, what is the underlying
problem and how are you going to address those?



See above. Then suicide, if that doesn't work ...

I think most of the other replies have just about covered everything. You
are sure it's not a failed exp. vessel.

Really a standard desludgant (eg X 400) should be all you need, together
with any or all of the following:

Power flush machine.
Main filling loop flushing.
Removal or radiators and hosing down.

After such wokr you may find that you still get some further blockage of
the 2ndary heatXer, but hopefully for the last time.


--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at http://www.diyfaq.org.uk
Gas fitting FAQ http://www.makewrite.demon.co.uk/GasFitting.html
Sealed CH FAQ http://www.makewrite.demon.co.uk/SealedCH.html
Choosing a Boiler FAQ http://www.makewrite.demon.co.uk/BoilerChoice.html
Gas Fitting Standards Docs he http://www.makewrite.demon.co.uk/GasFittingStandards