In message
,
harry writes
On Jun 7, 8:25*pm, cf-leeds wrote:
Hi,

It's fallen on me to replace the piping and rads for my parents'
central heating system.

The radiators are very old and badly sludged, as is the piping. The
piping is actually plastic piping, which was fitted in the late 70s
and has now started to deteriorate, to the extent that an upstairs
radiator pipe recently developed a crack (while they were on holiday
naturally), causing a serious flood. Hence time to rip out the lot.

I don't know what the official name for this black plastic tubing is,
but the only difference between it and copper seems to be that you
need both a nipple and olive for the compression fittings.

I now want to use 10mm copper pipe for ease of install, but would also
like to use a flexible *22m pipe from the boiler flow & return, to the
upstairs and downstairs manifolds.

Can anyone advise on whether this is possible. Is there such a thing
as a 22m plastic pipe, which can use a compression fitting onto the
existing bolier flow and return, as well as the manifolds ? This is a
vented system, so pressure shouldn't be too high.

I'm not interested the speed-fit type solutions, as I simply do not
trust them for long-term installations.

I can manage 10mm copper from the rads to the manifolds, but for the
main flow and return to the bolier, there's no way I can install 22mm
copper in the current pipe runs, which are the original black plastic
pipes. If I can find a flexible plastic solution, I can obviously just
tie the new pipe to the old and draw them into position.

Any advice appreciated.

Chris

Note that there is special plastic pipe for heating systems. It has
an "oxygen barrier", Keeps air from seeping through the porous
plastic. (Rots the radiators).

Yup, though it seems often that is the only type sold, probably not
worth carrying both types.

It's common to use copper pipe up to the manifold(s) where the pipes
go off to individual radiators.

Though AIUI, the OP wants to use plastic on this run because of access
issues.

small point though, the OP says he wants flexible pipe so he can pull a
run through, without joints. Whilst the plastic pipe is flexible, it's
not flexible like a hosepipe . so depening on the ipe run could still be
difficult if it needs sharpish bends.
--
Chris French