On 14/02/2013 09:50, Andrew Gabriel wrote:
In article ,
GB writes:
On 14/02/2013 08:52, harry wrote:
On Feb 14, 1:10 am, DerekG
wrote:
Ive got a large, heavy & expensive but otherwise ordinary radiator to
which I want to fit a Honeywell "Rondostat" digital TRV.

Sadly it has an LED display that can't be read with the 'stat in the
traditional location at the bottom.

The question is if I re- arrange the hot water inlet to use the top
tapping will the bottom half of the radiator still get hot ?

DerekG

Diagonal connections will give you the maximum heat output. The
manufacturers heat ratings are all for diagonal connections because it
makes them look more efficient.

Diagonal connections are the traditional way radiators are connected.
Using the two bottom connections is just done to make the pipework
look neater. And save a bit of pipe.

Does it make any difference whether the water goes in at the top and out
the bottom, or vice versa?

No difference at all.
The outlet has to be at the bottom, but the inlet can be anywhere.
If you feel a radiator with inlet at the bottom, you will see the
hot water rises by convection to the top in the first vertical
channel. It makes no difference if this happens inside the radiator
or if you pipe it to the top outside the radiator.

The only time the inlet must be at the top is for a gravity fed
system (no pump), to generate the dynamic pressure difference
in the height of the radiator which generates the gravity flow.


This needs to be clarified as it doesn't fully answer GB's question. I
once got a TIBO the wrong way round and I got a hot bottom entry area
and hot at the top and everywhere else cold. I cannot stress that if
choosing a top connection, it must be on the flow side and the exit must
always be a bottom connection.