On Tue, 5 Oct 2010 00:21:19 -0700 (PDT), Jonathan wrote:

Our wood burning stove with a back boiler has its own valves and pump
and only pumps water when the thermostat attached to its pipes
indicates it's hot enough. I have the thermostat set at 45C and it
certainly warms the radiators.

And what happens when you have a good fire burning and you get a
power cut? Just when you need the heat from the wood burner you have
to put it out to stop the boiler boiling or possibly exploding.

The circuit from a wood burner or other stove should be gravity and
have a passive heat dump for when the cylinder has reached 90C...

--
Cheers
Dave.