Does it have a timer & thermostat? START Is it a combi boiler? No Does it have a timer & thermostat? START Yes Central heating timer & thermostat to be installed with boiler Does it have a timer & thermostat? No Yes Yes No Controls meet first requirements System satisfactory No additional components required Central heating timer & thermostat to be installed with boiler Weather compensation Select one of the following to be installed alongside the combi boiler Flue gas heat recovery Load compensation Smart heating controls