Hi all,

For various reasons, I want to replace the downstairs radiators on my
1970ish Y plan heating system, along with their plumbing. There are
currently four large radiators downstairs. I'll be adding more when I
get to work on an extension in the spring but, for now, I just want to
replace those four rads.

My current plan is to run "backbone" pipework in 22mm plastic from the
controls in the airing cupboard, through the floor void to each of the
rad positions. I'd do the drops from the backbone to the rads in 10mm
plastic to make installation quicker and to keep the chase depth down to
a minimum.

Does this sound like a really stupid thing to do? A quick look online
seems to suggest that opinion is divided on plastic in general and 10mm
in particular...

Cheers,

Colin.

Gonna be harder to find plastic if you want to drill the wall!

Brian

--
From the Sofa of Brian Gaff Reply address is active
"Colin Stamp" wrote in message
...
Hi all,

For various reasons, I want to replace the downstairs radiators on my
1970ish Y plan heating system, along with their plumbing. There are
currently four large radiators downstairs. I'll be adding more when I
get to work on an extension in the spring but, for now, I just want to
replace those four rads.

My current plan is to run "backbone" pipework in 22mm plastic from the
controls in the airing cupboard, through the floor void to each of the
rad positions. I'd do the drops from the backbone to the rads in 10mm
plastic to make installation quicker and to keep the chase depth down to
a minimum.

Does this sound like a really stupid thing to do? A quick look online
seems to suggest that opinion is divided on plastic in general and 10mm
in particular...

Cheers,

Colin.

On 23/01/2013 13:23, Brian Gaff wrote:
Gonna be harder to find plastic if you want to drill the wall!

Brian


Good point. I think you can get metallic tape. Otherwise I'll use steel
capping.

Cheers,

Colin.

On 23/01/2013 13:39, Colin Stamp wrote:
On 23/01/2013 13:23, Brian Gaff wrote:
Gonna be harder to find plastic if you want to drill the wall!

Brian


Good point. I think you can get metallic tape. Otherwise I'll use steel
capping.

Cheers,

Colin.

Assuming you use pipe on a coil, you are going to need steel capping to
keep it in place prior to replastering.

FWIW I just replaced some 10 mm copper drops with 15 mm copper, boxed
in, because of inadequate flow on the 10 mm. Part of that though was a
blockage which I never located, either from solder or from a flat or
kink in the copper somewhere.

On Wed, 23 Jan 2013 14:02:11 +0000, newshound wrote:

FWIW I just replaced some 10 mm copper drops with 15 mm copper, boxed
in, because of inadequate flow on the 10 mm.

This is well worth noteing, the wall thickness of plastic is higher than
copper. How big is the ID of 10mm plastic, can't be much...

--
Cheers
Dave.

On 23/01/2013 15:00, Dave Liquorice wrote:
On Wed, 23 Jan 2013 14:02:11 +0000, newshound wrote:

FWIW I just replaced some 10 mm copper drops with 15 mm copper, boxed
in, because of inadequate flow on the 10 mm.

This is well worth noteing, the wall thickness of plastic is higher than
copper. How big is the ID of 10mm plastic, can't be much...


Indeed - it won't be much. The big question is, does it need to be much?

My previous house had some pretty big rads on 8mm copper, with much
longer runs than I'm planning, and the system worked fine for the 13
years we lived there. I wonder how 8mm copper compares to 10mm plastic.
I need to do some more digging...

Cheers,

Colin.

On 23/01/2013 14:02, newshound wrote:
On 23/01/2013 13:39, Colin Stamp wrote:
On 23/01/2013 13:23, Brian Gaff wrote:
Gonna be harder to find plastic if you want to drill the wall!

Brian


Good point. I think you can get metallic tape. Otherwise I'll use steel
capping.

Cheers,

Colin.

Assuming you use pipe on a coil, you are going to need steel capping to
keep it in place prior to replastering.

A clout nail either side of the pipe every so often will also do the job..


--
Cheers,

John.

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On 23/01/2013 15:59, John Rumm wrote:
On 23/01/2013 14:02, newshound wrote:
On 23/01/2013 13:39, Colin Stamp wrote:
On 23/01/2013 13:23, Brian Gaff wrote:
Gonna be harder to find plastic if you want to drill the wall!

Brian


Good point. I think you can get metallic tape. Otherwise I'll use steel
capping.

Cheers,

Colin.

Assuming you use pipe on a coil, you are going to need steel capping to
keep it in place prior to replastering.

A clout nail either side of the pipe every so often will also do the job..


I've used hot melt on cables in the past. I guess I'd run into trouble
here unless I remembered not to use the rad until after the plaster had
gone off...

Cheers,

Colin.

On 23/01/2013 14:02, newshound wrote:

Assuming you use pipe on a coil, you are going to need steel capping to
keep it in place prior to replastering.

Yep. It'll certainly need something. Steel capping looks like the best
bet to hold it down and make it detectable.


FWIW I just replaced some 10 mm copper drops with 15 mm copper, boxed
in, because of inadequate flow on the 10 mm. Part of that though was a
blockage which I never located, either from solder or from a flat or
kink in the copper somewhere.

This is the main worry for me. JG reckon 10mm is good for nearly 2kW at
11C drop. They don't say what length of pipe that's for though...

Cheers,

Colin.

On Wednesday, January 23, 2013 4:26:16 PM UTC, Colin Stamp wrote:

JG reckon 10mm is good for nearly 2kW at
11C drop. They don't say what length of pipe that's for though...
Cheers,
Colin.

It also depends on how many elbows, what pump speed and what temp drop.


NT

On 23/01/2013 16:26, Colin Stamp wrote:


This is the main worry for me. JG reckon 10mm is good for nearly 2kW at
11C drop. They don't say what length of pipe that's for though...


Not sure that length is an issue - within reason. The limit is usually
based on keeping the water velocity below the level where it starts to
get noisy.
--
Cheers,
Roger
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Please reply to Newsgroup. Whilst email address is valid, it is seldom
checked.

On 23/01/2013 13:09, Colin Stamp wrote:
Hi all,

For various reasons, I want to replace the downstairs radiators on my
1970ish Y plan heating system, along with their plumbing. There are
currently four large radiators downstairs. I'll be adding more when I
get to work on an extension in the spring but, for now, I just want to
replace those four rads.

My current plan is to run "backbone" pipework in 22mm plastic from the
controls in the airing cupboard, through the floor void to each of the
rad positions. I'd do the drops from the backbone to the rads in 10mm
plastic to make installation quicker and to keep the chase depth down to
a minimum.

Does this sound like a really stupid thing to do? A quick look online
seems to suggest that opinion is divided on plastic in general and 10mm
in particular...

Cheers,

Colin.


Thanks for all the replies on this. I thought I'd post an update.

The new rads are now on, with the 22mm Speedfit backbone pipework and
10mm copper drops to the rads. I filled the system and fired it up for
the first time a couple of hours ago. There were a couple of weeping
compression joints, but all of the Speedfit stuff seems to be
watertight. After a bit of very crude balancing I have no radiator
temp-drops over 10C, even with all the TRVs wide open.

It was a bit chilly for the day-and-a-half it took to swap everything
over, but we're back up to a toasty 18.5 now. I'm dead chuffed )

Right - time to sweep up. There seems to be an awful lot of wall on the
floor. I think I have some plastering to do...

Cheers,

Colin.