"The Natural Philosopher" wrote in message
...

I don't know what turns *your* boiler off. In my case it turns itself
off when the temperature of the water in the return path matches its
internal thermostat settings.

Yes, but the point is that it then turns itself *on* again when the boiler
itself has cooled to below its stat setting - regardless of whether any
heating is needed in the house. This is clearly wasteful.

Roger