Gravity feed piping

[mhes]

Hi

I am thinking of putting in a woodburning stove with a back boiler leading to a hot water tank. My problem is the tank position in relationship to the stove. It looks like I can either:

1) Have a 1.5 metre rise from the stove and then 7 metre horizontal run to the hot water tank.

2) A gradual rise of 25cm over 2 metre length from the boiler, steeper rise raising the pipework to 1.5m above the stove (3m length of pipework) and then just over 3m horizontal pipework to the water tank.

The return flows will be similar but in reverse. I suppose I have two questions:

a) Is it safe to have a long horizontal section of pipework in a gravity feed system?.... or can you have no horizontal pipes.
b) Does the heat dump (in this case a water cylinder with a coil) have to be at the highest point of the system, or can the pipework continue to rise and then drop after a sufficient length of pipework in order to get the circulation working?

Thanks

 

[kevplumb]

1) Have a 1.5 metre rise from the stove and then 7 metre horizontal run to the hot water tank.

not ideal but its what i would go for

best of a bad job

 

[doitall]

The thing that needs the consideration is the open vent and cold feed, and it must rise continuosly.

The flow pipe could rise above the cylinder provided the vent is at the highest point, but the return must fall back to the boiler.

The project needs expert design and installation.

 

[kevplumb]

****e john if you dont get the the initail rise it wont work

 

[doitall]

s***te john if you dont get the the initail rise it wont work

See the blo-ody mods been at the edit button again

You can rise to a high point with a gravity flow circuit Kev, provided the return fall continuosly from the cylinder back to the boiler.

Think ladder systems

 

[mhes]

Thanks for the replies. I suppose if I try and engineer even a slight rise on the horizontal and use the immediate 1.5m rise to get the process moving with a continuous drop on the return AND the vent at the highest point ..... it might work!

 

[doitall]

Thanks for the replies. I suppose if I try and engineer even a slight rise on the horizontal and use the immediate 1.5m rise to get the process moving with a continuous drop on the return AND the vent at the highest point ..... it might work!

What I didn't say and suppose I should.

As with any gravity circuit it can and most likely will reverse circulate when the heat source is off, more so if the flow rises and drop down.

for example you find the cylinder is cold in the morning because all the heat has gone back to the boiler.