Gravity feed pipe sizing

[Deleted member 2053]

Anyone got any info about pipe size/run lengths v total heat load for gravity systems. All I was ever taught was that you needed to use 28mm pipe to connect your gas boiler to the primary of your HWC. Connecting a woodburning boiler to a thermal store is a somewhat different ball game!

Not found anything useful by using google.

Ta

 

[AWheating]

the cylinder must be suitable for gravity/solid fuel systems
primary pipework to be a min diameter of 28mm
primary circuit as short as possible
cylinder to have a min of 1m and max of 6m head
pipework to keep rising inclined as steep as possible
fit a self setting temp pressure relief valve on the cylinder
heat leak rad/s with 22mm pipework
open vent to be a min of 19mm ID
feed to be a min of 13mm ID
controls to meet part L of the building regs
float to be copper
overflow to be copper


most of this is from hetas.

theres a way of figuring out the actual pipe sizing, but you need to know the correct temps and distances to work out the force of the water, and frictional restrictions of the pipework and cylinder. Somebody brighter than me may be able to guide you better on this tho 🙂

above all you must follow the stoves and the cylinders manufacturers instructions.

http://www.solidfuel.co.uk/pdfs/link_up.pdf

 

[Centralheatking]

I think Mr. Wheating is a solid fuel Jedi centralheatking

the cylinder must be suitable for gravity/solid fuel systems
primary pipework to be a min diameter of 28mm
primary circuit as short as possible
cylinder to have a min of 1m and max of 6m head
pipework to keep rising inclined as steep as possible
fit a self setting temp pressure relief valve on the cylinder
heat leak rad/s with 22mm pipework
open vent to be a min of 19mm ID
feed to be a min of 13mm ID
controls to meet part L of the building regs
float to be copper
overflow to be copper


most of this is from hetas.

theres a way of figuring out the actual pipe sizing, but you need to know the correct temps and distances to work out the force of the water, and frictional restrictions of the pipework and cylinder. Somebody brighter than me may be able to guide you better on this tho 🙂

above all you must follow the stoves and the cylinders manufacturers instructions.

http://www.solidfuel.co.uk/pdfs/link_up.pdf

 

[AWheating]

LOL, more jabba the hutt then yoda.

 

[Dickie]

I could pipe size it for you matey, but it would be one hellva big domestic boiler to have an output requiring anything bigger than 28mm.
What's the output of the boiler & 'sludgebucket' size?

 

[Deleted member 2053]

Thans for the useful replies. Sorry about the delay - actually managed a few days off!

Had already mailed the makers of the wood burner but they appear to be in chocolate fireguard mode.There is nothing in the destructions ref the pipe sizing.

The boiler output to water is 16.8kw and the store is 350 ltrs. The pipe runs are good - about 6 mtrs with the return having a fall of about 2 mtrs. I can do maths but don't have any idea how fast water can be expected to wang arorund the pipework. e.g. if we were looking at a temperatue rise of 20C from the boiler at full output we would need a flow rate of around 750mm/sec. To me this seems a bit high for gravity but it may actually be perfectly reasonable.

Thanks