"IMM" wrote in message ...
"Aidan" wrote in message
om...
What is the best inhibitor to use in this sort of system anyway? I was
going to get some more Fernox MB1 but it's a bit pricey (£19/4l).

No idea, I don't know what's in any of them. I use Fernox or Sentinel.
Corrosion is cheaper, in the short term..

Sentinel X-100 is far cheaper and just as good.

Some of the old combined pressure hot water & heating (i.e. the hot
water tank acts as a pressure vessel for the heating) types you're not
allowed to put inhibitor in because of possible contamination of the
potable water.

My old sealed system used to be like this & when it eventually stopped
working I found that a lot of the pipework was almost completely
silted up. It didn't help that the original install had the pump
pumping down so that air got trapped in. I now have a replumbed
sealed system with inhibitor & everything is fine.