It certainly would cost extra. Chasing walls out is a horrible messy job, and no plumber/installer would do that free of charge. I would'nt and i dont know any of my mates who would either.

To clear up a few misconseptions on here, as long as the boiler is big enough, (KW's)then you can fit another rad directly off the existing, flow and return. Dont cross them unless you have 2 way TRV's fitted. Make sure on one rad at least, that you have 2 lockshields, usually the bathroom is the place. If you have an old conventional system, you may, have to back fill as the system will have been designed with an exact amount of rads, plus they are usually sludged up. If its a combi the filling is easy, you might have to throttle the valves down to balance the system if the new rad is not getting hot, which means your boiler cant cope or your system is full of sludge.

24KW is good for about 6 rads

28KW 7 rads upto about 9 max

30KW 9 rads

upto 35KW will handle 10 rads

All again though is dependant on the size of the house, length of pipe runs ans size etc...

A 28KW will do a great job in a 3 bed semi, but not in a big detached. You get the drift. You would'nt expect a 1.3 valencia enginge to easily pull a 7.5 tonne truck would you.


Webby.