On Jun 7, 11:51*am, Tabby wrote:
On Jun 7, 6:28*am, harry wrote:





On Jun 6, 6:35*pm, Tabby wrote:

On Jun 6, 6:24*pm, harry wrote:

On Jun 6, 1:18*pm, (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?

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

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.

Why not just restrict the flow in the shorting pipe more? With an
adjustable valve.

NT- Hide quoted text -

- Show quoted text -

This would prevent the whole system from working!

how on earth would adding a little more restriction do that?

NT- Hide quoted text -

- Show quoted text -

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.