up and down radiator pipes

HI, been popping in and out of here for a while and have now joined. Great forum!

I have a question that in my books and this forum i cant really find much of answer for. I wonder if you can help.

I have built an extension on my house and now i want to add 4 radiators. The combi condenser boiler can handle it and i know how to plumb.

What i am not so clear on is:

My exsisting pipes come out the bottom of the boiler (boiler is on ground floor) and some go down and round downstairs, and for upstairs they simple go up the side of the boiler and into the now uncovered ceiling. Now the easiest way for me to add my radiators is to connect to the flow & return in the ceiling, run between my joists into my extension and then come down the walls to my ground floor extension radiators. What concerns me is will this work as i am kind of creating an up over and down effect with my pipes and so i am worried about trapping air and the rads not working.

Any help would be greatly appreciated.
cheers.

YOu're right about the air, so each pipe will need an air bleed point, to which you will need to have access. Automatic ones could be used, but they can leak eventually. Usually the neatest place for an access panel is above the boiler, but avoid bleed valves with rubber in them there because it can go hard, stick shut etc because that's the hottest water. You then get a high pressure jet of hot water down your arm.

Check these: go to the site and see the page these item numbers are on

http://www.bes.ltd.uk/products/graphics/16383.png
http://www.bes.ltd.uk/products/graphics/12078.gif

iIf its a pressurised\sealed system is it still necessary for bleed points on the inverts?

(this is a question and not a comment)!

Yes even a non vented system will trap air in the goal posts when filling.
P

Goal posts

cheers flufster.

what if i was to bleed the radiators for ages, perhaps open the valves without the radiator connected and just let loads of water through, would that get the air shifted?

May i also add that there is a radiator to plumb in in the roof space of the extension, would that get rid of the air as it is higher than the top of my goal post, but a little along the line?
And even though its a just a few rads with not much flux and solder, do i need to flush the system

The problem isnt the air on initial refill its the air that will occour due to the oxygen in the fresh water being released over a period of time and the creation and collection of gas due to corrosion within the system that will be the future problem.