We have fitted, a Heatline Monza 24KW condensing combi boiler. It has 24v and 240v connectors, although I'm lead to believe the 24v is just for the boilers built in controls.
The programmable thermostat is a Homexpert(Honeywell) THR870CUK, 7 day program, two wire, 'VOLT FREE' jobbie, that...