Greenstar i
Green display, pressure gauge on the left, +/− heating buttons. Also covers i Junior and many i System boilers.
Greenstar CDi Compact / Si Compact
Two rotary knobs. Heating is the left knob with the radiator symbol.
Greenstar CDi Classic
Older two-knob fascia. Heating is the left knob, hot water is the right.
Greenstar 2000
Round control with a separate pressure gauge on the right.
Greenstar 4000
Round control. Press the radiator key, then up or down to set the flow.
Greenstar 8000 Life
Round white buttons around a central screen. Radiator key sets the maximum flow.
Greenstar 8000 Style
Black glass round control with a flame light at the top.
Match the picture to the boiler in front of you. kW size (25i, 30CDi, 4000 30C and so on) does not change how you set the flow. Combi, system and regular versions of the same family usually share the same fascia.
Oil boilers such as Danesmoor and Heatslave, and floor-standing Highflow CDi, are not on this list. Look those up on Boiler Manuals.
When the flow is set, go back to the Boiler Optimiser to log what it was and what you set.