pipe sizes for new rads

[steviep]

HI Guys

I have central heating only upstairs, anyway the real flame fires dont push that much heat out and currently considering (esp after last 2 winters) fitting rads to lounge and kitchen, bringing the pipes down from a tee in the bedroom in the alcove next to chimney breast to minimise the visuals and removing bonded solid wood floors.

all the existing rad pipes are 15mm, im looking around 2000w for each rad, would 8mm dia copper pipe be adequate to supply them both

thanks

Steve

 

[ecowarm]

Welcome to the forum Steve, its not an easy question to answer. Do you have 22mm pipes under the floor boards?

 

[dontknowitall]

It depends on the run but I'd go for 10mm as a minimum.

To work properly (as Ecowarm has hinted) they must be tee'd off the central heating circuit (which is usually 22mm and under the landing). If they tee off another radiator both rads might fight for heat and could be impossible to balance properly and you might end up with a worse situation.

And Welcome!!

 

[steviep]

Thanks for replies, the CH flow pipe is 22mm and branches to 15mm under floor from boiler, one way to 1st bedroom rad and the other way to small bathroom, not sure where they go after that until i get some carpets and boards up its a 3 bed semi.
if new pipes were 15mm would that reduce balancing/fighting for heat probs

 

[Simon F]

the smaller the pipe size, the more resistance to flow. best to take the feeds for the 2 new radiators from the 22mm flow and returns if possible to avoid problems with flow. you could come of the 22mm in 15mm then tee off in 10mm to the 2 new rads. probably best to stick to 15mm but difficult to be clear without visualising the layout.