Thermostat Central Heating

[pwdrive]

Hello Paula, don't quite follow that one ?

lawrence.

[AlanBeckett]

Nor me I'm afraid.
Could you draw it?
Alan

[Joe]

I think I've got it. Instead of running the Flow straigt to the first upstairs raditor take it via a higher point to increase the effective Head.

- Joe

[Mark R]

I think that's it Joe, running the pipes up the stack into the attic space, then down to the first radiator.

cheers Mark

[AlanBeckett]

That sounds to me like a good method of generating a air lock
If there is a higher attic space then that's the place to put the Header. That's what increases the Head.
Alan

[pwdrive]

If we are talking about a gravity flow system I can not see how that can work, any air bubbles in the system will find their way to the highest point as they will contain some hydrogen at that point, the gas will form a thermal barrier to any heat convection.
If however we are talking about a pumped flow the so called gain of extra head and hence pressure can be replicated by increasing the speed of the pump (and hence the pressure) as most pumps have at least three speed settings, I am not a hydraulic engineer so any comments welcome.

Lawrence.

Edit: Allan beat me to it so read in conjunction with.

[Michaelr]

I think you have got it Lawrence. If it was gravity flow"your problem" would be even worse to get started.You cannot gain energy by raising the height of the feed. The energy available and needed for flow is determined by the height of the header tank and trapped air would definitely be an issue

Mike

[pwdrive]

Yes Mike that is correct, just to round up we live in a single storey house it is "low slung" ie: roof pitch = 25 Deg. the internal hieght from floor to underside of the roof apex is barely 12 ft.
One top edge of the main CW tank is right up against the ceiling at the highest practical point. The ceiling is vaulted ie: it's the underside of the roof) this leaves a "shed" as in weaving warping etc, that area is just large enough to get a CH header tank in, the top side of one of its edges is also right up against the ceiling (underneath side of side of roof) The stove is approx. 3 ft high and stands on a 4" hearth, the top of the boiler outlet tappings are at the same hieght less about one half inch. The HW tank is approx 3 ft high so as can be seen the scope for a steep and therefore fast gravity flow at start up is greatly reduced hence the little problem when first firing up with a fast burning fire, I could fire it up more slowly but this gain would be offset by condensation problems in the last few feet if the chimney/flue before that chimney/flue has had time to heat up past any critical dew point.
The trick that Paulas dad used might apply to a different situation that what I am describing, so I will see if Paula can describe in more detail.

Lawrence

[Mark Hennessy]

Hi Lawrence,

Thinking laterally about your problem, the answer is obvious: dig out a cellar and move your boiler down there. Simple!

(runs quickly away from computer!)

Mark

[pwdrive]

Hi Mark, the laterall solution could quickly turn into a vertical problem as we live on top of old copper mine workings, you weren't to know so no problem.

Lawrence.