On 19/08/2020 07:51, Charles F wrote:
Hi All,

A query re central heating long term maintenance. I replaced mine in its
entirety about 10 years ago - it's a sealed system with new rads, mostly
plastic pipework, and a new boiler about a year after that. It's had Fernox
F1 added at the recommended concentration from the start, supplemented when
needed, and has a magnetic filter on the return to the boiler - which
doesn't collect much of anything. When I've needed to remove a rad the water
is clear, and there is usually only a small amount of what looks like black
iron oxide particles in the very bottom of the radiator.

My query is - do I just continue with an occasional extra bit of F1 added,
or after ten years is it a good idea to drain, wash through with clean
water, and refill with new F1?

With a nice clean system like yours, there will be no benefit in a
drain and refill (unless you need to for other reasons).

Each time you refill you add fresh oxygenated water, and that will allow
more corrosion - or at least mop up more of the oxygen scavenger in the
corrosion inhibitor.

So basically, keep doing what you are doing.


--
Cheers,

John.

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