Hi,

I'm havining a go at installing all the pipework and rads for a new (combi boiler) central heating system to keep the costs down. All seems to be going OK, but I've got a question. I live in a bungalow and therefore becuase my pipework has to run through the roofspace, it's higher than all the rads and the boiler. Basically my flow and returns and both inverted loops. What do I use to vent the air at the top of these loops. I know it probably sounds like a stupid question, but I've been to B&Q and some of the online DIY/plumbing stores and the choice isn't very clear. There's lots of advice around about venting air from radiators, but that doesn't really help me. The main 'backbone' of the system in the roof is 22mm copper pipe if that's imporant.

Thanks in advance.