On Saturday, February 16, 2013 4:01:07 PM UTC, Andrew Gabriel wrote:

Convection forces are very important. The hot water rises instantly in

the first channel, and the rest of the radiator behaves as TBOE, with

the hot water descending uniformly down all the other channels, as it

cools, and remains stratified almost equally across them all. See

http://www.paceplumbing.co.uk/images...r-flushing.png

I'm starting to change my mind on this. That image does seem to show all the hot water (white area) going straight up the first channel. Presumably the waterways are oversized (relative to a pipe) for the flow rate that is going through them.

I'm not wholly convinced since the 'before' picture on that site does not show what I'd expect from a sludged-up radiator. There are numerous thermal images of radiators on the internet, but none as 'black & white' as this one; they've probably chosen an image that best suited their sales patter.

TBOE connections would seem to be a waste of time unless you want the valves high up. The extra heat is probably due to the extra pipe.

On Sunday, 17 February 2013 07:09:15 UTC, harry wrote:
On Feb 16, 7:58Â*pm, Onetap wrote:
On Saturday, February 16, 2013 7:00:30 PM UTC, harry wrote:
If you have ever had a system run purelyb y convection you will

realise what a puny force it is.

In a pumped system, it is neither here nor there.

Â* I have.

Â*It can be a significant factor, but then I could work it out if I felt inclined.

Â* The differential pressure, provided by the pump, Â*across the radiator is throttled down in the course of balancing until the flow is adequate.

Â* Most radiators can work adequately on a one pipe system with no diverter tees (Harry will have to google for that), with convection alone driving nearly all of the flow through the radiator. That suggests to me that the differential pressures across the rad, whether provided by pump or convection, may be of a similar order of magnitude.

Â* It's a hypothetical question since no-one would knowingly connect a radiator TBOE with the flow in the bottom. I don't see why it wouldn't work, is all.

Â*It was a useful exercise, since my pondering of this gave me a bloody good idea about something else.

I am very familiar with with one pipe heating systems having spent
forty years in the NHS where they are universal in older hospitals
thanks.
And without diverter tees (which can be sweep tees, or cup tees),
radiators work very poorly indeed.
This should be obvious or it would not be neccessary to make such
tees.
The main reason for a top connection is to give the diagonal
connection (and hence a better water distribution pattern) and to put
the control valve at a convenient height.

I have read this whole thread with interest thanks. It strikes me that it would be just as good to connect the f and r at the top on opposite sides of the radiator. Any thoughts

On Fri, 16 Mar 2018 11:06:23 -0700, hallnorm99 wrote:

Any thoughts

Yes, it seems you can't read dates! This is a 5 year old thread!

--
TOJ.

On 16/03/2018 19:35, The Other John wrote:
On Fri, 16 Mar 2018 11:06:23 -0700, hallnorm99 wrote:

Any thoughts

Yes, it seems you can't read dates! This is a 5 year old thread!

At least he had the decency to quote the post he was replying to.

On 16/03/2018 18:06, wrote:
I have read this whole thread with interest thanks. It strikes me that it would be just as good to connect the f and r at the top on opposite sides of the radiator. Any thoughts

Return must be at the bottom. Otherwise the cold water at the bottom
never moves, and the hot runs across the top.

Andy