This is a bit of a saga, but I will try and be brief. In August 2004 my warm air system packed up, so I forked out for the installation of a fully pumped Honeywell 'S' central heating system. Everything worked great, but there seemed to be a lot of air circulating noisily through the pipework/rads (esp as I have concrete floors downstairs - hence a few exposed inverted loops). After a few weeks of daily air bleeding, the installers came out and reduced the pump speed (!).
This seemed to reduce the problem slightly, but nevertheless when the system started from cold, a lot of gurgling/bubbling from the loft indicated that air was still being drawn in. A few weeks later still and I called them back. This time the chap made some alterations to the vent pipe in the loft, and added a bridging pipe between the cold feed and vent pipes in the airing cupboard (crude air separator?). This appeared to resolve the problem. Plus it was autumn/winter so I didn't feel like taking any more time off work to have the system farted about with (that, and my growing distrust of plumbers!).
So here I am, rapidly approaching another winter. Now the CH is coming on regularly, I am back on the bleeding rounds. There doesn't appear (to my layman's eyes) to be anything wrong with the pipework: the CH vent pipe has more than 18" of head above the expansion tank in the loft, and the pipe exit itself is a couple of inches above the level of water in that tank. There are no leaks from any rads or visible pipework. The only way I can see air getting in is by being sucked back in through the vent pipe (rather than hot water/steam being pushed through).
I have just purchased an official air separator (British Gas approved, apparently) which I am considering getting someone to fit in place of that bridging pipe, but am unsure if that would be a waste of money. Other, less sane ideas include lengthening the vent pipe so that it exits below the water level in the expansion tank - so it would suck water back in rather than air, or fitting some sort of non-return valve to it!
At this stage I am open to any views or advice that users of this forum may wish to share.
Thanks in advance,
James
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This seemed to reduce the problem slightly, but nevertheless when the system started from cold, a lot of gurgling/bubbling from the loft indicated that air was still being drawn in. A few weeks later still and I called them back. This time the chap made some alterations to the vent pipe in the loft, and added a bridging pipe between the cold feed and vent pipes in the airing cupboard (crude air separator?). This appeared to resolve the problem. Plus it was autumn/winter so I didn't feel like taking any more time off work to have the system farted about with (that, and my growing distrust of plumbers!).
So here I am, rapidly approaching another winter. Now the CH is coming on regularly, I am back on the bleeding rounds. There doesn't appear (to my layman's eyes) to be anything wrong with the pipework: the CH vent pipe has more than 18" of head above the expansion tank in the loft, and the pipe exit itself is a couple of inches above the level of water in that tank. There are no leaks from any rads or visible pipework. The only way I can see air getting in is by being sucked back in through the vent pipe (rather than hot water/steam being pushed through).
I have just purchased an official air separator (British Gas approved, apparently) which I am considering getting someone to fit in place of that bridging pipe, but am unsure if that would be a waste of money. Other, less sane ideas include lengthening the vent pipe so that it exits below the water level in the expansion tank - so it would suck water back in rather than air, or fitting some sort of non-return valve to it!
At this stage I am open to any views or advice that users of this forum may wish to share.
Thanks in advance,
James
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