Re: [OT] Air in central heating

[Jim Noble <yahoo-groups@xxxxxxxxxxxxxxxxxx>]

kw1816 wrote:
> I've replaced a couple of radiators in a normal wet central heating
> system, flsuhed it through and added inhibitor but I keep getting
> air trapped in the first rad upstairs (which happens to be the
> bathroom!) This has been hapening for over a month.
>

I had similar problems with my old central heating (it's just been
replaced). The pipe from the F&E tank had become clogged, and so the
system wasn't being refilled.  As the water was heated, it expanded and
overflowed into the tank via the vent pipe, thus when it cooled and
contracted again, air was being sucked into the system. This was
collecting in the bathroom towel radiator (the highest radiator in the
system).

Because the feed was blocked, bleeding the bathroom radiator more often
than not resulted in air being drawn into the radiator rather than being
expelled out.

Could it be that in flushing the system through, you've displaced some
crud in the F&E tank which has blocked a pipe somewhere? (Mine had a
couple of sharp turns in the pipe from the F&E tank to where it joined
the system just before the air separator/vent pipe junction - clogging
was inevitable I suspect).

That's assuming you have a vented system, of course :-)

Jim