On Mon, 19 Jul 2010 07:07:08 -0700, dog-man wrote:

What's the best stuff to clean a secondary heat exchanger?

Periodically, mine needs a degunge and I use normal bog standard
descaler such as a kettle descaler.

For descaling the DHW side I use Kilrock-K ("inhibited formic acid" IIRC)
- which is also sold in diddy little bottles as kettle descaler. Then fit
a proper scale inhibitor (http://yaph.co.uk/limescale/) to stop it
happening again.

If it's blocked on the primary side then a powerflushing machine with a
PHE adaptor seems to do the trick temporarily but you'll need to address
the cause of the problem which probably means powerflushing the whole
primary system and/or fitting a Magnaclean/Boiler Buddy/equivalent filter
to the primary circuit to remove/catch crap circulating around it.



--
John Stumbles -- http://yaph.co.uk

I used to think the brain was the most interesting part of the body
- until I realised what was telling me that