Connection pipe between woodburning boiler and overhead storage tank

[jbolland]

Hi,
I'll be installing a (vented) buffer cylinder above a woodburner and will have a 28mm connecting copper pipe for the convective heat transfer. The vertical distance is about 3m. Two questions: Is it best for the connecting pipe to enter at the top or bottom of the buffer cylinder? (I think it should be the top) and (2) if I install a check valve in the pipe (to prevent backflow through the boiler when the fire is off) will it affect the normal convection flow?

 

[tamz]

Top
Don't fit a check valve

 

[justlead1]

Gravity circulation wont travel down to boiler(unless pumps are involved at cylinder)