Thanks Andrew.

When you say it was quite easy to clean, do you mean for a Corgi
registered person?

I had a quote of £520 to have it replaced (£200 for the parts, the
rest labour). The engineer mentioned that another alternative would be
to connect a special pump to the cold and hot inlets that pumps Furnox
through the whole system.

Can anyone recommend any of these pumps or whether they work?

Can I get the same effect from any of the other limscale removers I
have seen on the Internet that use magents/radio/etc?

Regards
Neil

Andrew Gabriel wrote:
In article .com,
"Neil" writes:
I have been told I need to replace the secondary heat exchanger on my
Potterton Combi 80 due to limescale stopping the HW from remaining hot
(CH is fine)

As the boiler is approx 5-6 years old, would money be better spent on a
new condensing boiler?

Is there no way of removing the limescale rather than purchasing a
brand new exchanger?

I cleaned up a friend's one a few months back. It was quite easy.
That was a Baxi 80, IIRC. The instructions will tell you how to
remove and replace the heat exchanger. Watch that when you release
the pressure, the water doesn't spew out over anything important
such as the circuit boards, gas valve, etc.
Buy a tub of Furnox DS-3, dissolve some in warm water, and keep
pouring through the heat exchanger until it stops fizzing. You
will likely need to mix up fresh solution several times (each
time it goes blue, IIRC). Try to avoid getting any undissolved
crystals of DS-3 into the exchanger, and flush it out well
afterwards.

Flush out the other side too with a strong water jet -- it can
fill with black crud which floats around in older heating systems
(particularly if you didn't have enough inhibitor at some time).

--
Andrew Gabriel