On Feb 6, 8:35*pm, " wrote:
Why not put in a mains pressure tank *you won't need expension tanks?

Not with a solid fuel appliance - these must have an unpressurised
circuit, as there's no way to shut them down once fired up. They must
also rely on gravity circulation (in case of a power cut).

Caveat - I've never fitted a solid fuel rayburn - only a modern
pressure-jet oil burner. However solid fuel was one of the options I
considered and I had a good think abut how I'd route it in my own
place, and nosed about at other installations.

For your f&e, your routing sounds ok to me. But the main boiler to hw
tank in 28mm - I'd take great care to ensure you follow the Rayburn
installation instructions exactly, to ensure that you have excellent
gravity circulation. Both pipes slope upwards all the way, minimum
number of bends, heat-leak radiator etc. Otherwise you may for
evermore be plagued by kettling/knocking in your boiler.

That doesn't preclude the use of mains pressure cylinder.
The Rayburn needs one gravity circuit in case of pump failure to take
away excess heat. This can be a radiator or the hot water cylinder.
If you have never had a fuel range before, they are a very labour
intensive and filthy business. Cooking on a Rayburn in not in the
least like cooking with electricity or gas. Most people get fed up
with the experience quite soon.
They are a tool of last resort, for places where the electricity
supply is uncertain and there is no gas.
As a source of heat, the boiler is small and very inefficient.