"TheScullster" wrote in message
news

wrote

Hi all,

I added a radiator to my sister's central heating system and fitted a
snip.........

Other responders assume this is a pressurised system - can't see that in
the original post.
But, in any case.......
Have you switched any zone valves in the system to the manual position ?
There may be one three-way valve OR maybe one or more two-way valves.
Moving these to the manually open position greatly improves the drain/fill
operation.

Phil


Is it just a case of the system needs balancing as you have added 1 radiator
and increased the size of the other?
Close the valves on the rads nearest the boiler to let the other rads have
more heat.
Can the boiler cope with the additional rad and the larger other radiator?