Hi there

My CH system uses 8mm pipe - and all the rads use yorkshire valves -
where both feed and return pipes go in at the same side of the rad. I
want to fit TRVs - and maybe change all my rads, without ripping out
all the pipework.

Can I:
1 Fit new rads
2 Use some sort of 8mm10mm adapter on the pipework
3 The use standard 10mm TRVs

I am a complete novice, and in the process of planning what I'm going
to do with the system.

Any help appreciated.

Kind regards

Simon
www.thehawthornes.org

On Sun, 10 Oct 2004 18:46:54 +0100, Simon Hawthorne
wrote:

Hi there

My CH system uses 8mm pipe - and all the rads use yorkshire valves -
where both feed and return pipes go in at the same side of the rad. I
want to fit TRVs - and maybe change all my rads, without ripping out
all the pipework.

Can I:
1 Fit new rads

Yes, but you may not to be able to increase the size. If the boiler
is a conventional 82degree flow, 70degree return, then over typical
distances of a few metres from a main pipe or manifold, 8mm pipe will
only support a flow able to deliver about 1500W.
If it's a condensing boiler, you could have temperatures of 70 and 50
degrees, but the radiators are derated relative to their output at
82/70.

You can work out the situation by looking at manufacturer data sheets
for the radiators and looking at the deratings to 89% and 60% for each
scenario.


2 Use some sort of 8mm10mm adapter on the pipework
3 The use standard 10mm TRVs

Yes you can. I used 15mm TRVs on the radiators and adaptors from
8mm female to a 15mm tail that go into theTRVs. This gives a neat
solution.

For your situation, you could take one length of 8mm pipe behind the
radiator to achieve a neat job.

Pipe benders (a hand tool) for 8mm tube are available very cheaply.


I am a complete novice, and in the process of planning what I'm going
to do with the system.

Any help appreciated.

Kind regards

Simon
www.thehawthornes.org

..andy

To email, substitute .nospam with .gl

On Sun, 10 Oct 2004 19:07:04 +0100, Andy Hall
wrote:


For your situation, you could take one length of 8mm pipe behind the
radiator to achieve a neat job.


Thanks for all this Andy. I was going to change the boiler - so had a
few quotes (new condensing boiler, new rads & pipework, tank etc) -
varied between £9k and £13k.

Just looking to sort out the rads for now - don't need any more power,
but just want to control the power I have. Planning on concentrating
on drafts and insulation for now (and I have lots of drafts and almost
no loft insulation).

Regards

Si