Hi

I need to replace one radiator and also replace the valves on another. Ive
never done drained the system before so I thought I would ask the experts.

My main confusion is whether there is valve that I can open on the Vaillant
VCW GB240H combi boiler (at least that is one of the three model numbers on
the instructions).

I have put a picture of the pipework at
http://www.atbn38.dsl.pipex.com/boiler.jpg

I have workred out the following. There is a braided pipe that goes from 1
to 2 with a valve at each end. If I open both these ( as I have done in the
past) then water is added to the system. The pipe at 2 is hot so is
therefore the heating circuit whereas pipe at 1 is the cold water supply. I
therefore assume that 3 is where the cold water supply supplies the hot
water system.

The valve at 4 has some kind of locking mechanism on hte right hand side and
has a connection to the overflow pipe. Is there something here I can use to
drain the system ? Do I turn of the mains to hte boiler first ?


To re-fill the system, do I simply start refilling the system ? Should the
boiler be on so I can feel the hot water in the radiators ? I guess I need
to open the bleed valves ? Shall I do this on one radiator at a time ?

I tried searching for a step by step guide but failed miserably. Can anyone
help ?

Thanks

Tim