External Programmer / Timer
If there is an external programmer, or timer on the boiler, please ensure that these are set to an On 24/7 position. Many programmers/timers will call this 'Man'

Signal
Press a button to illuminate the Thermostat display and ensure there are at least 2 signal bars showing on the top left of the display.

Central Heating
Press the 'CH MODE' key until the CH Selector hovers over Man.

Press the ' /\' key to raise the temperature until you see a flame icon appear on the Thermostat.

Check that the boiler has fired up and any zone valves (if applicable) have moved to their appropriate positions. Press the 'CH MODE' key again to turn the central heating off.

Hot Water (if applicable)
Press the 'HW MODE' key until the HW Selector hovers over Man.

Check that the boiler has fired up and any zone valves have moved to their appropriate positions. Press the 'HW MODE' key again to turn the hot water off.

If the boiler does not fire up, you may already have a full tank of hot water. In which case, temporarily increase the cylinder stat to max for this test.