On 20 July, 14:20, (Andrew Gabriel) wrote:
In article ,
* * * * David writes:



On 19 July, 18:25, (Andrew Gabriel) wrote:
In article ,
* * * * dog-man writes:

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.

It does work, but I was wondering if there is anything better which is
safe to use?

Furnox DS-3 is the stuff to use. It's Sulphamic (not Sulphuric) Acid,
plus an indicator dye to tell you when it's used up, plus a scent so
you don't drink it. You used to be able to buy it in B&Q, and builders
merchants used to stock it, but the larger tubs have got harder to
find, so I order it from BES.

Interesting, will there be any harm in using the sulphuric acid
though? I have already got a bottle and just about to pour it in the
heat exchanger.

That's really a question for the manufacturer.
Depends what the heat exchanger is made from.
It's probably ok with stainless steel. Heated sulphuric acid
can corrode some stainless steels and the walls tend to be very thin,
but you aren't going to have it in contact for long. If it's not
stainless steel, then you'll have to say what it is.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

It's a stainless steel from a Vaillant turboMAX