Log burner on Gravity

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Hi Folks, bit of a tricky one here /

Ground floor Cylinder
1st floor Log Burner
2nd floor f+e tank

Can i run the log burner flow up to the 2nd floor complete with feed and expansion connections and then down to the cylinder and back up with the return to the log burner.

Will this circulate on gravity

Any ideas !!!!!!
 
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Can you get the circuit to run in a circle? ie return down from cylinder and back up to stove, flow fro stove up to fe tank and vent then back down to cylinder?
may need heat leak etc
If so it will pi##s round ;)
 
Yeah ,,,


Circle yeah , up around and down.

Is this the best way of doing it as i can`t move the cylinder or the stove
 
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It may work, but log burners and water heating are generally not good news.
 
It may work, but log burners and water heating are generally not good news.

unless you got free fire wood :D

oilman see that post with the guy runnung an oil pump with plastic plugs in?
 
Not tricky at all. It won't work.
I beg to differ

Differ away.

Gravity circulation

1) Heat source/Stove at low level, heats the water.

2) The water expands and rises being displaced by colder, denser water descending from the heat dump/cylinder at high level.

3) Heat dump/cylinder at high level cools the (primary) water.

4) The water contracts and descends, being displaced by hotter, less-dense water ascending from the heat source/ stove at low level.

5) See 1 above.

So how will a ground floor cylinder and 1st floor stove work by gravity?

It won't work.
 
The hottest point will be the top of the circuit, the coolest the bottom, what is put in between doesnt matter, as long as the stove isnt the highest point it will work.
As soon as the stove heats and any water rises from the stove it has to be replaced with return water coming up from the cylinder.
Where else will the water go and come from :?:
 
As soon as the stove heats and any water rises from the stove it has to be replaced with return water coming up from the cylinder.
Where else will the water go and come from :?:

As soon as the stove heats and any water rises from the stove, it has to be replaced with cooled water descending to the stove. So you need the heat dump/cylinder above the stove.

It is a cycle, that's the way it works, the water goes around and around.

Your theory has the water ascending from the stove, replaced with water ascending from the cylinder below. Do you wind up with all the water in the attic? The water in the stove will boil.

It won't work. The end.
 
The best way to get a gravity circuit working at its most efficient is to bring the return to a low point and back up to the return connection of the heat source.
In this scenario it means the hottest point in the system will be at the vent tee to the f&e tank, then the water will reduce temperature and drop down to the cylinder through the coil cooling all the time, still go down then rise back to the stove and start again.
In effect the cylinder is in the return loop on the down cycle.
This loop will work even without a cylinder or anything in the circuit as long of course as there is enough heat loss to satisfy the heat output of the stove.
Ideally yes the cylinder would be above the stove, but it isnt.
It doesnt mean it wont work.

Try thinking outside the box
 
There's one similar to it on the Dunsley schematics. Not sure if its on their website. They recommend fitting a check valve to prevent the boiler heating up due to the piping arrangement encouraging back circulation.
 
draw me a picture of your theory please.

I have, unfortunately your not looking over my shoulder :LOL:


Take a look at Dunsley web site, they have a scenario for an unvented cylinder connected to a heatlink (pumped of course).
You will see a flow pipe rising and descending with an aav on top, then dropping to a gravity circuit to act as a heat leak radiator circuit.
The high point is the AAV then everything else from that point is efectively return pipework.
 
Take a look at Dunsley web site, they have a scenario for an unvented cylinder connected to a heatlink (pumped of course).


Pumped? You mean gravity circulation won't work?

Can you post the link to that, please?

If the heat-link is a neutraliser, then that's the heat dump, with secondary pumped circulation to dissipate the heat.

Getting back on topic, the system proposed by the OP won't work.

Try thinking outside the box? What box? Could I suggest you try thinking within the laws of physics? It's not hard; hot fluid expands, rises to the top above cooler more dense fluid. It's how convection works.
 

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