"Rob Nicholson" wrote in message
...
There is something rather unwell with my heating system but it's never
been
quite right since I bought this house. Current problem is the radiator
nearest the boiler and pump (which is upstairs in the back bedroom) is
continually filling with air. Bleed it and it goes hot instantly but will
be
full of air in a couple of days. Air and bubbling can also be heard in and
around the boiler/pump.
snip
I recently drained the system twice in order to remove and decorate behind
a
radiator in the bedroom.
snip

When you drained the system, did you run it for a while with a flushing
compound then drain it again then refill with an inhibitor such as Fernox?

A long time ago I had a problem with one radiator constantly filling up with
air (or other gass(es) ) and was advised that this could be the result of
corrosion of the inside of the radiators. This gets worse when you add fresh
water - apparently the water can stabilise a little after time.

I ran with the flushing compounr, flushed the system, then added fernox and
the radiator stopped filling with air.

Another indication that all is not well is if the water coming out when you
bleed the radiator is blackish instead of clear.

Have you ever flushed/treated the system?

Could be worth a go.

HTH
Dave R

P.S. not talking about power flushing - just running with a treatment in for
a week.
There used to be regular threads about the benefits/not of power flushing.
Basically you can save a lot of money by cleaning out your system yourself
e.g. by taking individual radiators off the wall then flushing them through
with a hose pipe outside.
Having said all this, my neighbour had his system power flushed because
radiators were not heating up, and he said there was an amazing difference.