On Sat, 31 Oct 2009 12:36:50 +0000, newshound wrote:

time I tried a chemical clean on the removed heat exchanger using formic
acid (kettle descaler) plus flushing. Not the ideal chemical approach,
hydrochloric acid (brick acid) would be better but this can be bad for
stainless steel heat exchangers.

I tried fairly concentrated HCl on the PHE and on a sample of the gritty
magnetic crud blocking one up and it had no effect on them.


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

I've got nothing against racists - I just wouldn't want my daughter to marry one