Bigger core pipes for central heating system??

rob7475

So are you saying the heating feed pipe runs upstairs, feeds the rads up there before coming back down and feeding the ground floor rads?

Are you able to turn the valves off to the upstairs radiators to see if downstairs gets any hotter? Easy if you have TRV's, if no TRV's you'll need a spanner to turn off the lockshield valves (they usually have a plastic cap with a screw in the middle - remove cap, turn the usually square bit clockwise until it tightens up. Make sure you count how many turns for when you turn it back on).

calleyw

rob7475 wrote: »

So are you saying the heating feed pipe runs upstairs, feeds the rads up there before coming back down and feeding the ground floor rads?

I guess so. As the pipes come out the top of the combi boiler to the little bedroom straight above it then around up stairs.

Then a pipe comes from the attic and feeds down stairs.

Yours

Calley

unclebulgaria

martinsurrey wrote: »

15mm pipes are fine for a few rads on runs off 22mm pipes.
but after putting the plastic inserts in you're down to a 6mm hole.

a combi boiler, which typically pumps water at about 1.5m per second just cant get enough hot water through that 6mm hole to feed 3-4 rads.

I've had to fix a system like this, and it was my fault, replaced 22mm copper with 15mm pushfit plastic, upstairs got hot, downstairs luke warm at the tops, replased back to copper and all good.

I wasn't going to comment on your post but, you're talking absolute rubbish.
Your first statement is correct, 3 rads off a run of 15mm is about fine anymore and you risk flow issues.
Your second statement is just plain tosh! How do you explain microbore piping, when its clean, feeding radiators? For a start the insert doesn't make the hole 6mm, plastic piping develops less resistance than copper because it can be laid in long lengths with sweeping bends that have less resistance so the occasional insert wouldn't make much difference.
Your third statement, well I'm not sure what you were thinking there!