Hello,

I have 22mm pipe that goes from the boiler to a tee where it is
reduced into two 15mm branches: one branch serves upstairs front
radiators; the second branch serves the upstairs rear radiators. It's
the same set-up for the downstairs radiators: 22m pipe tees to 15mm
for the front and another 15mm for the back. And finally there's a
22mm pipe that goes to the hot water cylinder.

I'm having a bit of a rearrange of pipes ready for my new boiler and I
wondered if all three feed pipes go upstairs (to pump and valves in
airing cupboard) will one 22mm return pipe be sufficient to carry the
combined returns? Logic suggests if three pipes carry water up, I
would need three pipes to bring the water back down? Or would the one
22mm pipe cope, the flow in the return pipe just being faster than in
the individual feed pipes?

I'm thinking of bringing the pump and valves downstairs to the boiler,
to create space in the airing cupboard and reduce the noise at night.

Thanks,
Stephen

Stephen wrote:
Hello,

I have 22mm pipe that goes from the boiler to a tee where it is
reduced into two 15mm branches: one branch serves upstairs front
radiators; the second branch serves the upstairs rear radiators. It's
the same set-up for the downstairs radiators: 22m pipe tees to 15mm
for the front and another 15mm for the back. And finally there's a
22mm pipe that goes to the hot water cylinder.

I'm having a bit of a rearrange of pipes ready for my new boiler and I
wondered if all three feed pipes go upstairs (to pump and valves in
airing cupboard) will one 22mm return pipe be sufficient to carry the
combined returns? Logic suggests if three pipes carry water up, I
would need three pipes to bring the water back down? Or would the one
22mm pipe cope, the flow in the return pipe just being faster than in
the individual feed pipes?

Dunno, but the cross sectional area of a 22mm pipe is just over twice that
of a 15mm pipe if that helps, so presumably 1 x 22mm can carry slightly more
that 2 x 15mm?


--
Dave - The Medway Handyman
www.medwayhandyman.co.uk

"Stephen" wrote in message
...
Hello,

I have 22mm pipe that goes from the boiler to a tee where it is
reduced into two 15mm branches: one branch serves upstairs front
radiators; the second branch serves the upstairs rear radiators. It's
the same set-up for the downstairs radiators: 22m pipe tees to 15mm
for the front and another 15mm for the back. And finally there's a
22mm pipe that goes to the hot water cylinder.

I'm having a bit of a rearrange of pipes ready for my new boiler and I
wondered if all three feed pipes go upstairs (to pump and valves in
airing cupboard) will one 22mm return pipe be sufficient to carry the
combined returns? Logic suggests if three pipes carry water up, I
would need three pipes to bring the water back down? Or would the one
22mm pipe cope, the flow in the return pipe just being faster than in
the individual feed pipes?

I'm thinking of bringing the pump and valves downstairs to the boiler,
to create space in the airing cupboard and reduce the noise at night.


I am note sure that I fully follow what you propose, but if the flow and
return to the boiler are both 22mm pipe at the moment then I would not
expect you to need a larger pipe anywhere in the system - given a normal
sized house.

If you don't have a sealed system, then you need to ensure that the header
tank feed and the overflow are always unobstructed.

--
Michael Chare