On Sat, 27 Jan 2007 10:25:39 +0000, Siggy wrote:

I wish to do a thorough descaling and de-sludging of my sealed CH
system, and have bought a large tub of Fernox DS40 to accomplish this (I
hope).

I note on the instructions that it says to allow 7 days for it to work
on all-steel systems, but only 4 *hours* for those containing aluminium
rads.

My problem is that I have a combination of both.

Can anyone suggest a work-flow I can use here to ensure a proper job is
done throughout, please?

Note: My system is split into 2 circuits, with flow control valves
operated by the timer programmers. All the aluminium rads are located on
the downstairs circuit and the older steel one's on the upstairs.
Obviously, I *can* isolate the alu rads by screwing down the valves, but
this would mean I would have no heat to downstairs at all for around a
week, and winter is not over yet. And no, the job can't wait until the
Spring. However, if it's a must, then I will do it. :-(

Nigel

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

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


--
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