How effective is convection?

I understand the concept of gravity circulation to heat a cylinder (heated water loses density and hence rises up through cooler water).

If the upstairs radiator circuit t's off of the gravity circuit from near to the upstairs located cylinder then obviously the pipework is more horizontal. A pump is fitted to drive water around this circuit when the cylinder is satisfied.

Without this pump I believe I am right in saying that these upstairs radiators get hot gradually. If yes then is this caused by the flow initiated by the gravity circuit or is it caused by convection? Or both? Does it usually just extend to one or two rads or can it do quite a few?

With a pump (but not switched on) would the upstairs rads get hot eventually (i.e. can whatever is happening get past the pump?)?

Go back a hundred years, and the whole heating system was gravity powered, so even if the pipes are a lot smaller, the rads will get some heat eventually.
I suppose I am not telling you anything new when mentioning that a gravity system is seriously outdated.

bengasman said:

I suppose I am not telling you anything new when mentioning that a gravity system is seriously outdated.

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Except with wood burning stoves

Goldspoon said:

Except with wood burning stoves

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Fair enough, although, is burning wood to heat the house not a bit outdated and cumbersome compared to mains gas?

bengasman said:

Fair enough, although, is burning wood to heat the house not a bit outdated and cumbersome compared to mains gas?

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It is.

There is, however, a market for it and it is growing: fueled by people's fear of gas running out, or the suppliers restricting supply and the price going up.

Some people (forestry workers and their mates as an example; landowners as another) get free wood so heating home and water becomes free.

Some people just like the feeling of being self sufficient (two fingers to the gas and oil industry).

Some people enjoy the whole "obtaining wood, storing wood, chopping wood, "havin' a fire" experience).

Unlike boilers, which most mere mortals cannot get stuck into when something goes wrong, fires, pumps and pipestats are "understandable" and easily obtainable. This provides a feeling of "taking control back" and saving on maintenance bills.

There are, of course, the negatives. However - fires can be linked with gas/oil boilers and combis: so the best of all worlds if it all works nicely together.

I suppose we are now well and truly off topic

I have wood fired heating as where I live there in no gas and I wont pay oil or electric prices. Plus I get free wood LOL.

Our school has a huge 250kw biomass boiler which uses wood pellets, given a lot of trouble since day one and the caretaker has to go INSIDE the boiler every week to de-coke it despite the automatic cleaning mechanisms.

The boiler is extremely noisy in operation and creates dust in the plant room which gets into the pumps and causes them to fail. A cyclonic separator is fitted.

Thankfully the school has 6 200kw Hamworthy Wessex gas boilers.

It's different to a wood stove system I know............................

In Lithunia the people burn only logs and sticks as oil and gas is too expensive (or the people too poor)
Thats what the big Lithunian guy I work with tells me anyway.