Gravity fed central heating..... Aghhhhh ! ! Can anyone help

[Sunnydays]

Hi
We have bought a house in Bulgaria. We are currently renovating (read re-building) the house (dilapidated shell).
There is no gas out here, and the electricity supply is very hit and miss in our village.
All the homes here are heated by a wood burner and the whole family just lives in 1 room all winter.
We are looking to have a normal house and install central heating from the wood burner... The thing is, we can get wood burners with water tanks on them by order. And we can get modern immersion tanks with 1 and 2 coil systems made for the European market. But that is about it.
I can find very little information on gravity fed systems... I know, I know, they are no longer legal in the uk etc etc. But we have no other options unless we want wood burners in every room and to spend a fortune on wood each year (not an option).
As a child I remember our school having a gravity fed central heating system and friends who had the same in their houses.. and although it is not the ideal system, It does work and does a reasonable job, especially with winter temps here of -20.
I know this is a very non-pc subject but I also know many engineers worked on these systems in the past. As the saying goes 'there is never an engineer when you want one' So I'm hoping they are like buses and now several will appear at once Lol
I can balance the BTU's of the woodburner with the boiler and radiators its the system set up I cannot find any help with.
This is kind of the idea...I am thinking to set up the immersion boiler directly above the woodburner, in the bedroom and 1st in line with the radiators with a temp valve on the boiler outflow. With twin coil so we can use solar heat for the water in summer and woodburner heat in the winter.
If anyone knows anything about these systems and could spend some time talking it through with me I would be very grateful as I have come to a bit of a standstill with the planning of this area.
And may have to end up, muddling through with best guess trial and error
Thank you in advance for any help

 

[Whitespirit66]

Are you confusing gravity fed with gravity circulation?

If you have any land, you may consider ground source heat pump or poss air source.

 

[doitall]

Not much good without electric WS.

Gravity system are simple and certainly not illegal in the uk afaik.

A plan or rough shape of the property would help.

 

[Charnwood]

If you have any land, you may consider ground source heat pump

GSHPs can be fed by a vertical borehole as opposed to horizontally-laid coils, so land may not be an issue.

 

[doitall]

No damn good without a reliable electric supply Charnwood

 

[Servotech]

I like how these diagrams always show the bore holes to be straight whilst in practice they veer off at all kinds of odd angles

servotech,

 

[ianmcd]

As Doitall has correctly pointed out the OPs biggest problem is unreliable electricity so unless they get some sort of generator or battery store then he is a bit limited to what he can use to heat the place

 

[Boilerman2]

A properly designed Gravity loop is exactly what the OP needs, no electricity needed for safe operation - as said a drawing of the building would help

 

[Servotech]

Hi
We have bought a house in Bulgaria. We are currently renovating (read re-building) the house (dilapidated shell).
There is no gas out here, and the electricity supply is very hit and miss in our village.
All the homes here are heated by a wood burner and the whole family just lives in 1 room all winter.
We are looking to have a normal house and install central heating from the wood burner... The thing is, we can get wood burners with water tanks on them by order. And we can get modern immersion tanks with 1 and 2 coil systems made for the European market. But that is about it.
I can find very little information on gravity fed systems... I know, I know, they are no longer legal in the uk etc etc. But we have no other options unless we want wood burners in every room and to spend a fortune on wood each year (not an option).


As a child I remember our school having a gravity fed central heating system and friends who had the same in their houses.. and although it is not the ideal system, It does work and does a reasonable job, especially with winter temps here of -20.
I know this is a very non-pc subject but I also know many engineers worked on these systems in the past. As the saying goes 'there is never an engineer when you want one' So I'm hoping they are like buses and now several will appear at once Lol
I can balance the BTU's of the woodburner with the boiler and radiators its the system set up I cannot find any help with.
This is kind of the idea...I am thinking to set up the immersion boiler directly above the woodburner, in the bedroom and 1st in line with the radiators with a temp valve on the boiler outflow. With twin coil so we can use solar heat for the water in summer and woodburner heat in the winter.
If anyone knows anything about these systems and could spend some time talking it through with me I would be very grateful as I have come to a bit of a standstill with the planning of this area.
And may have to end up, muddling through with best guess trial and error
Thank you in advance for any help

I'm old school trained and have worked on gravity systems in the past.

You need big pipes - 28mm primaries with a steady rise all the way to the cylinder (level at least).

You are allowed a dipped return to the boiler this is something like 1/10 of the circulating hight (you need to know what you are doing to get this to work so I would try and avoid any dipped returns).

For the heating side I would go with a one pipe system with a 22mm pipe right around the property taking off short stabs for the radiators and just valve one side of the radiator (you need to avoid as many restrictions as possible).
If you have any double radiators take the stabs off in 22mm with a 22mm valve.
Again keep the heating main level and avoid any dips and do not reduce the main at all.
It leaves the boiler in 22mm and returns in 22mm, understand!

These are just the basics of a gravity install and it as become quite a specialist area these days with very few plumbers understanding let alone knowing how to install it successfully.

Good luck.

servotech,

 

[Boilerman2]

You have forgotten to mention two important considerations,
1. Radiators should be connected with flow at top of rad, return from the bottom opposite end to promote gravity circulation through the radiator
2. any TRV's must be single ipe type (high lift valves) danfoss and Drayton both make these (not cheap)

 

[Servotech]

I'm afraid it's a myth about taking the flow connection to the top of the radiator (it will achieve nothing except a sludge build up over the years at the bottom corner of the radiator).

I cannot recommend TRVs either for this system just one wheel valve/ rad; the bigger the better.

Like I said not many plumbers these days understand gravity systems.

servotech,

 

[Agile]

OP, before you discount a gravity heating system, don't lose track that a circulating pump uses less than 100 watts and can be driven from a very small generator.

Or better a battery charged from a solar panel and a small inverter using the mains to aid charging when there is mains available.

Gravity hot water cylinder is needed to prevent the stove overheating.

Tony

 

[doitall]

I'm afraid it's a myth about taking the flow connection to the top of the radiator (it will achieve nothing except a sludge build up over the years at the bottom corner of the radiator).

I cannot recommend TRVs either for this system just one wheel valve/ rad; the bigger the better.

Like I said not many plumbers these days understand gravity systems.

servotech,

Gonna have to take issues Servotech.

Tboe is without any question the best way to get a gravity system to circulate, unless you raise the rads off the floor a foot or so.

Full flow TRVs are workable with a gravity system, if it installed correctly.

The rest of your posts on the subject is debatable.

If the flow rises from the heat source, then circulation is nearly guaranteed, irrespective of the orientation of the return, the only problem with dips is air locks.

 

[Servotech]

Gravity is a very simple system stick to the basics because any attempt to complicate it will result in problems - keep it simple (take note HETAS) is my advice.

Adding to my above notes regarding the one pipe central heating system using swept tees for the radiator stabs would be a big positive.

Gravity is very lazy and won't do any hard work.

servotech,

 

[slapper]

I'm afraid it's a myth about taking the flow connection to the top of the radiator (it will achieve nothing except a sludge build up over the years at the bottom corner of the radiator).

I cannot recommend TRVs either for this system just one wheel valve/ rad; the bigger the better.

Like I said not many plumbers these days understand gravity systems.

servotech,

Gonna have to take issues Servotech.

Tboe is without any question the best way to get a gravity system to circulate, unless you raise the rads off the floor a foot or so.

Full flow TRVs are workable with a gravity system, if it installed correctly.

The rest of your posts on the subject is debatable.

If the flow rises from the heat source, then circulation is nearly guaranteed, irrespective of the orientation of the return, the only problem with dips is air locks.

Yer on the money DIA, TBOE defo best way on gravity. If he can get Electric then he can pump a two piper with the Primaries on gravity with heat leak off etc