Airlock in capped off pipe

Hi all,
Health warning : I am a complete numpty at plumbing and have never done any plumbing work in my life, so you'll have to speak to me as if I was a slighlty retarded kid...
So, here goes :
One of my sealed CH pipes is banging like mad when the boiler goes on. I think I have located the noise to an underfloor pipe which used to feed 2 radiators. These radiators have been removed in the summer and the pipe capped off. However, there is still a 2m section of horizontal pipe remaining.
From reading this archive, I believe an airlock might be causing this. The question, you've guessed it, is what can I do about it? Do I need to bleed the entire system (and if so, how?, and how do I fill it up again afterwards, in particular wrt corrosion inhibitor etc). Or is there a simpler way?
TIA
Greg
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Greg W wrote:

Drain the system and remove the 2m of pipe. You may be able to do it without draining by using one of those pipe freezer kits. Inhibitor is best injected into rad air vent plug using one of those Fernox cartridges, nb they are around 20 retail...
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wrote:

Thanks - however, the pipe is under some original wood flooring which I don't want to ruin by taking up, and above a newly plastered ceiling I'd hate to poke holes in for that very reason. Any fix which doesn't involve removing the pipe?
Cheers
Greg
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If you still have access to the capped ends of the pipe, fit vent caps instead & bleed as you would a radiator. Buy at a plumbers' merchant or DIY shed. Example here, but they charge for postage: http://www.bes.ltd.uk/products/148a.asp code 6793, half way down. You'll need one on both capped ends.
--
fred

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