I am getting a lot of air in my indirect central heating. The top floor radiators seem to be getting air in them daily. We have been in the house six years and though the system is not exactly a model of installation and has had some air in in the past this is now getting rediculous. Could the pump be causing this or what else?
Sorry to sound so clueless i am a fairly (i hope) competent DIYer but I'm a bit puzzled - and fed up of bleeding radiators (in both senses)
cheers Ged
If this is a vented system there ought to be a vent pipe - where is this in relation to the pump?
Is there water in the CH header tank?
It could be it is drawing air in through either the vent (can happen if it is too close the the suction side of the pump), or the header tank (say if the ball valve had got stuck).
It is also possible that the feed from header tank to CH pipework has become blocked...
Presumably it's a vented system with a small header tank in the attic?
Make sure that there is water in the header to cover the outlet by a couple of inches or so when the system is cold. [If the ball valve sticks and the level drops, you will suck air into the system] Make sure that, if there's a tap in the feed from the header to the system, it isn't turned off. Make sure that the system isn't "pumping over" - by which I mean a constant stream of water flowing from the vent pipe into the header when the pump is running. Make sure that what you're getting out of the rads *is* air and not hydrogen. [What happens if you stick a lighted match to it?] If it *is* hydrogen, it indicates that corrosion is taking place inside your system due to insufficient (or no!) inhibitor.
That gives you a few things to go at!
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