solid fuel pipework

[rascla]

hi guy, new to this first thread...
just wondering about the pipewrk from solid fuel stove, my question is, would it b ok to run flow on the gravity circuit, from stove to attic, then back down from attic space to coil on cylinder, and return back from coil to boiler, would this work

 

[buffy27]

u need to post some pics of drawings .this is not a diy job ..but if u think u are very competent u will need very specific advice .pipe size and layout with pump location are paramount for a correct installation !!

 

[rascla]

thanks for getting back to me buffy...

em its four tapping stove, opposite tapping for F+R for gravity and pumped (rads) its a bungalow so planned flow on gravity would rise maybe 7ft to abv ceiling level, across ceiling roughly four ft(above hallway) then expansion off to tank, and drop down to coil in hotpress, would this work do you think or can u see any problems with this set up....

 

[Gray0689]

what your saying is the right way to do it mate no problem remember to take vent off from highest point

 

[Bernie2]

Try Solid Fuel Association site and perhaps Dunsley, Rayburn or others to get some ideas as well.

 

[justlead1]

Hi. If you propose to use all four tappings (Gravity F & R and pumped circuit for rads) consider using an injector tee. The reason being, with opposed tapping (Unrestricted) the movement of water across the boiler created by circulator can have an effect on the gravity circulation of primaries. (pushing back water entering the boiler via gravity return. Reducing gravity circulation potential.) One other point the cylinder needs to be fitted as high as possible in the airing cupboard. (the horizontal centre line between boiler and cylinder should be as great as possible. The vertical line as small as possible. Good Luck

 

[prs1]

No it wont work, a gravity system works due to convection ie heat rises
I Think u need too get a HETAS reg before u cause an accident,
sorry but if your asking questions like that u shouldnt be trying to put one together if your not then leave it to the people that know!

 

[Gray0689]

Prs1 why would it not work the pipwirk is going up!!!!!
Like you said heart rises
Read the question again and think first?

 

[stevetheplumber]

i dont think it will work can you not put the cylinder in the loft with tanks on a platform above? this will increase preasure of hot and cold water as well

 

[lenny]

I have asked a similar question on another thread with no replies.

When a cylinder and/or a heat sink radiator is connected to the gravity flow and return pipework. The pipework needs to rise. You can't connect to the WBS , go up into the loft , through the loft and then down to the cylinder , the gravity circulation would not work.

The cylinder / heat sink radiator must be higher than the WBS.

I have attached a schematic of alternative method which I have used a few times.

 

[Gray0689]

Yes you can go in to loft then across as long as constant rise then down to cylinder as long as you have vent on the highest point and the cylinder bottom is above the stove height

 

[prs1]

So the water that is in the pipework in the loft is going to be hotter than the water thats entering the coil,
It would not be done like that on a gas boiler with gravity hot water,
and in principle i dont see that its any different other than possibly more dangerous if done wrong,
Why take the flow up into attic to go back down to cylinder,agreed it may work to some extent but it will be inefficient,surly u want as much heat to the coil not the loft!

 

[Gray0689]

There may be a bit of heat loss but if pipework well lagged with armaflex will be grand been doing it that way in northern Ireland for a long time

 

[prs1]

Just another point when you are not using you boiler/stove or whatever your using say at night time,because your flow is higher than your cylinder you will get reverse circulation ie all the heat in your cylinder will migrate back to your boiler due too heat riseing.
This is why its crucial that u get someone who is qualifiled in these type of systems as it is not a diy job,so seek professional design advise!
A diy job would invalidate any warentees on any products bought as well as your house insurance.
Atleast if dealing with a pro if there is any problems your covered,check out some of the suggestion that bernie has mentioned and good luck.

 

[Gray0689]

Well as I am qualified and done a lot like this then I think I know a bit about it and for your reverse circulation point you put on a flappy paddle non return valve

 

[Gray0689]

And also it would not matter what the primary heat sorce was whether it be gas or oil ect as will be separat for cylinder ie twin coil for DHW

 

[tamz]

thanks for getting back to me buffy...

em its four tapping stove, opposite tapping for F+R for gravity and pumped (rads) its a bungalow so planned flow on gravity would rise maybe 7ft to abv ceiling level, across ceiling roughly four ft(above hallway) then expansion off to tank, and drop down to coil in hotpress, would this work do you think or can u see any problems with this set up....

It will work no problem. Use 28mm for F&R, rise to expansion pipe then drop to cylinder. If a direct return route is hard to do, drop it below the floor about a foot lower than the joists and rise back to the boiler. Also you need to use a metal expansion tank if solid fuel. Use Armaflex Class O insulation rather than the the polyethylene (grey) type.

 

[justlead1]

Hi. It not an obsession about hot water rising? Its a combination of cooler water falling and hot water rising. The circulation height plays a big part in the effectiveness/efficiency of gravity circulation. Parasitic circulation will occur but not gravity circulation from a higher point too a lower one. At the time gravity was employed as the norm. Drawings depicting both the F & R passing into loft (above cylinder) both vented and then dropping to cylinder where available to students studying the trade. There have been a lot of changes to the plumbing and heating trade over the years but physics remain the same i hope. Needless to say 28 mm tube is the absolute minimum pipe size for such a job as described. It also worth noting that costs associated with solid fuel heating were not as great as the world we live in now. In fact keeping the loft warm to protect the CWSC was a selling aid. Funny no mention of the vents freezing when boiler was off.