jsee wrote:
I've been asked by a friend to install a Rayburn multifuel in a french
property of his. I have the following questions:

Do you know the model of the Rayburn?


1) He already has a cylinder for the hot water installed with immersion
heater which he says he wants to leave. So the system will be just the
central heating.

.... he's fitting an entirely separate system for the CH?


Are there any problems with this? Is it more advisable
to have a gravity run to the cylinder as a "heat bleed".??

That is what he ought to have.


2)If I run 5 large radiators off the Rayburn in a fairly standard 2
bedroom house what pipe sizing would you recommend? 22mm for the main
flow and return and 15mm for the radiator runs? The system will be
pumped.

Seems normal... the output of a Rayburn Supreme, which is
what I have installed, is 35KBTU. To maintain that needs
a bit of care - if ash builds up or fuel gets low it will
produce a good deal less heat. How large are the radiators?
How large is the 2-bed house? BTW, it can get through 25Kg
of Anthracite a day if you go at it.


3) He says I can just plug the pump in, are there any problems with the
pump being permanently on (whilst the rayburn has fuel in)? I can see

No problem.


problems if the pump is on a stat - the heat won't dissipate from the
Rayburn so I can't think of another solution other than manually
switching the pump on and off.

Has this Rayburn got a thermostat? If so, that and the heat
sink will be OK.


What fuse size for the pump inside the
plug -3 amps as that's all central heating usually has??

4) If I was to use gravity, what pipe sizes would I need? How much
extra warm up time would there be?

28mm from the boiler. Depending on how much water is
in the system , the fuel, and the size of the house,
it could take a couple of hours (or so!) to have the
system at running temperature from lighting up.


5) He wants to use car antifreeze in the system as the property will be
hardly used in Winter. Any problems with that?

Not at first sight, but I'm sure others will know
better...