On Wednesday, 6 December 2017 14:26:41 UTC, Tim Watts wrote:
On 06/12/17 13:49, whisky-dave wrote:
On Wednesday, 6 December 2017 13:12:13 UTC, Tim Watts wrote:
On 06/12/17 12:13, John Rumm wrote:
On 06/12/2017 11:25, Tim Watts wrote:
Most sites recommend a differential across the rad of 12C - but I wonder
if this was aimed at higher flow temperatures of yonder times?

Yup usually. With a modern condenser they often suggest you can go up to
nearer 20.

I manage with flow of 55C most of the year - so what would be a sensible
differential to aim for? 8C?

The bigger the differential, the more the condensing efficiency gain at
the boiler. However with a flow at 55 its not going to make a massive
difference anyway, and you may want it tighter to keep the heat output
of the rads up.

I was looking at it the other way around: if you have a high flow
temperature, then you'd expect a larger differential for a given flow
rate (l/min) as the temperature difference between radiator and room
would be greater, leading to greater loss of heat from the water.

And this si why I said I'd like the radiator really hot, hotter the better so more chance of heat coming from the rad to the air, but yuo claimed it;s better toturn the rad down for better cycling.

What on earth are you talking about?

He doesn't know. That or he has a steam powered bicycle.