In our 1979 house we replaced the old boiler with a Worcester Bosch
Greenstar jobby, and jolly good it is too. We left some of the old
rads, replaced some, some new. Also have a new wall thermostat.

In the new extension we installed underfloor heating on the ground
floor, run from the same boiler natch, but with a separate controller
and thermostat. At present we're experimenting with the best/most
efficient mix of heating.

However, we have found that if we leave the UFH on, then turning off
the normal CH at the controller has no effect. The CH controller is a
pretty standard box (I'm at work so I can't quote chapter and verse)
in that it has two sides - one for HW and the other CH, both with four
options - OFF, Once, Timer, ON.

Anyone any ideas why we can't turn off the CH? The plumber is
currently in Barbados (for which we seem to have paid, if the cheque
book stubs are anything to go by) so can't ask him.

Thanks

Edward