Going from 10mm to 15mm copper pipe for a new radiator

[mr_frank]

My combi boiler is located in the cellar which feeds 11 radiators in our house. The flow/return pipework coming out of the boiler is 22mm which steps down to 15mm further down the line as it goes off to different radiator points. Closest to the boiler are two radiators which providing heating for the cellar area, they are only small units and take a feed off the 22mm pipework down to 10mm pipe work.

I am moving a radiator around in a room above which will requires 15mm connections and was contemplating splicing into the 10mm pipework using copper reducers to convert up to 15mm. This would save the need to run extra copper pipe work across a room from an existing pipework location to feed the new radiator. Also to me makes sense as save the water travelling further than it needs to in order to warm the radiator.

Question is : is there anything issue with doing it this way?

 

[kirkgas]

If by spicing in to the 10mm you mean fitting tees to feed to rads off one 10mm pipe then don't, unless both rads are very small and close together they won't work fully, you need to cut into the 15 or 22, preferably the 22 but again depending on size of both rads you will get good heat distribution through both if they are fed from a 15 supply

 

[mr_frank]

thanks for the quick reply. Is there any science reason behind why going from 10mm to 15mm is not a good idea?

 

[Simon F]

the problem is the amount of heat that can flow though a certain diameter of pipe.
what size are the radiators?
typical flow rate :-
8mm - 1.5kw
10mm - 2.5
15mm - 6
22mm - 13
28mm - 22
you could possibly upsize,
but it sort of goes against logic of how flow and pressure/resistance all works

 

[ptr080]

did it yesterday,went from 10mm to 15mm upstairs to feed 1000mm DC down stairs on gravity fed system,was very surprised how good it worked,hotist rad in house,

 

[ptr080]

did it yesterday,went from 10mm to 15mm upstairs to feed 1000mm DC down stairs on gravity fed system,was very surprised how good it worked,hotist rad in house,

never affected other rads either