TRV on single pipe system
Andrew Gabriel
system, partly as an experiment (if it works, there are about
another 6 to do).
However, it seems not to work. The flow restriction through it
when fully open is too much resistance to get enough flow through
the radiator, resulting in a hot area along the radiator top only.
I might try moving the inlet to the top so the hydrostatic
pressure difference between the hot and cooling water helps the
flow, but I'm not hopeful this will make enough differemce to
notice.
Just wondering if anyone has come across any suitable product
for a single pipe system?
--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]
Tinkerer
"Andrew Gabriel" <and...@cucumber.demon.co.uk> wrote in message
news:isigip$nl$1...@dont-email.me...
Never used one so I am not familiar with their operation, but is it possible
to fit it on the outlet side of the rad?
--
Tinkerer
YAPH
> Just wondering if anyone has come across any suitable product for a
> single pipe system?
Fitted Danfoss RAS-C2s on the rads on my mum's single-pipe system
(actually two parallel single-pipe systems) and they work OK. Maybe just
a matter of getting more oomph from the pump?
--
John Stumbles -- http://yaph.co.uk
The ant has made himself illustrious through constant industry industrious
So what? Would you be calm and placid if you were full of formic acid?
harry
There were special TRVs for single pipe systems. It has much larger
valve body. There is no way you will get a two pipe system TRV to work
here.
I have had a look, no-one seems to be making anything anymore.
Your best bet is to get a motorised valve to control the circuit.
The pressure drop across the rad depends on the type of tees.
There are plain tees, swept tees and cup tees in ascending order of
preference.
Tabby
Why not just restrict the flow in the shorting pipe more? With an
adjustable valve.
NT
harry
>
> - Show quoted text -
This would prevent the whole system from working!
dennis@home
"harry" <harol...@aol.com> wrote in message
news:827539aa-d618-48a7...@c41g2000yqm.googlegroups.com...
>
> This would prevent the whole system from working!
It would increase the total head on the loop, it may still work, depending
on the pump.
If someone wanted to do that I would try an auto bypass valve to give a
small (0.1bar) head across the section.
It may cause noise /if/ the valve keeps opening and closing though.
Tabby
how on earth would adding a little more restriction do that?
NT
MJA
<discussion about single pipe system and full-flow TRVs edited out>
> The pressure drop across the rad depends on the type of tees. There
> are plain tees, swept tees and cup tees in ascending order of
> preference.
The Americans use Monoflow tees for single pipe systems, see:
<www.heatinghelp.com/article/17/Hot-Water/74/Diverter-Tee-Hot-Water-Heating>
I have never seen Monoflow tees for sale in the UK, but have come across
proposals to fabricate a venturi tee out of a tee and reducer, such as:
<www.torrens.org.uk/HowTo/Injector/index.html>
Anyone tried this to soup up an older UK single pipe system?
MJA
Andrew Gabriel
harry <harol...@aol.com> writes:
> On Jun 6, 1:18 pm, and...@cucumber.demon.co.uk (Andrew Gabriel) wrote:
>> Just fitted a TRV (Drayton TRV4) to a radiator on a single pipe
>> system, partly as an experiment (if it works, there are about
>> another 6 to do).
>>
>> However, it seems not to work. The flow restriction through it
>> when fully open is too much resistance to get enough flow through
>> the radiator, resulting in a hot area along the radiator top only.
>> I might try moving the inlet to the top so the hydrostatic
>> pressure difference between the hot and cooling water helps the
>> flow, but I'm not hopeful this will make enough differemce to
>> notice.
>>
>> Just wondering if anyone has come across any suitable product
>> for a single pipe system?
>
> valve body. There is no way you will get a two pipe system TRV to work
> here.
> I have had a look, no-one seems to be making anything anymore.
Ah, that was a good clue. They're called full flow TRVs, and it
looks like Danfoss still make them (single pipe systems are still
common in large commercial installations). Danfoss RA-G.
harry
The pumps are very low head/pressure on a single pipe system
(Resistance is low the pipe is of quite large diameter with no
obsructions.)
If you throttled any part of the single pipe it would affect all the
radiators.
harry
> On 2011-06-06, harry <haroldhr...@aol.com> wrote:
>
> <discussion about single pipe system and full-flow TRVs edited out>
>
> > The pressure drop across the rad depends on the type of tees. There
> > are plain tees, swept tees and cup tees in ascending order of
> > preference.
>
> The Americans use Monoflow tees for single pipe systems, see:
>
>
> I have never seen Monoflow tees for sale in the UK, but have come across
> proposals to fabricate a venturi tee out of a tee and reducer, such as:
>
> <www.torrens.org.uk/HowTo/Injector/index.html>
>
> Anyone tried this to soup up an older UK single pipe system?
>
> MJA
They are/were very common, usually screwed malleable iron. There were
even copper solder ring ones.
Many very large wet heating systems used them
harry
> In article <760d766c-f6d1-483d-b28f-34def9de9...@hg8g2000vbb.googlegroups.com>,
>
> - Show quoted text -
Yes that's the ones. We used them in hospital heating systems. (I was
a hospital engineer.)
They work a lot better if swept tees are fitted to the pipework rather
than standard tees. They don't rely on convection to circulate water
through the radiators.
Can't find anybody supplying these either. I suppose they must be out
there somewhere. Crane used to do them.