In uk.d-i-y, Derek Geldard wrote:
On Sun, 02 Apr 2006 22:55:32 +0100, Tim
wrote:

They seem to have been de-emphasised now with the advance of sealed
systems and a better understanding of pumping -over.

Thanks Andy & Derek. Curiously the heating installation had this
deaerator and a couple of those ball float designs, which seemed a bit
redundant to me.

Derek, I am curious of your remark about the 'better understanding of
pumping'. Could you clarify this or point me to a URL please?


I also had the Myson one that Andy mentioned. That one was new and
boxed and came with an propaganda leaflet that illustrated all the
myriad possible "wrong" ways of setting up the feed and expansion,
flow and return piping, and the siting of the pump in order to avoid
such nasties as "pumping - over" or negative pressure in parts of the
system.

The leaflet implied the one sure fire way of avoiding all the problems
was by using a Myson Aerjec.

Apparently this was an issue of concern at the time, this was 25 years
ago. Since one encounters these things so infrequently and most new
build houses since then have been built with wet c/h without a
proprietory de-aerator, I presume that eventually the optimum set up
became the norm.

We had one fitted here, in about 1997. We were having a new boiler
installed in a different room and going from a gravity-fed-hot-water
system to a fully pumped system. Pipe-routing and space considerations
meant that the layout was not what the plumber would consider ideal, and
the pump had to be located upstairs in the airing cupboard rather than
down by the boiler. The plumber expressed reservations about all this,
muttering something about air bubbles, and recommended a de-aerator.
This could all be complete ******** of course, but it made some kind of
sense to me in that a pump operating in "pull" mode instead of "push"
mode might cause air induction or make air come out of solution.

Anyway it's no trouble, and I don't imagine it cost very much. The
boiler has always made quite a lot of air-bubbling noises, though.

--
Mike Barnes