No Central Heating from a Ferroli F30B?

I have a Ferroli F30B. Have just received a letter from their Customer Services saying they can't send an engineer, nor sign me up for "Care Service". No engineers in the area seem know about them or have time to fix it before winter sets in. So, I have to fix it myself!

The hot water works fine. The clock works fine. the thermometer seems fine. No CH. Not even a CH light comes on. Any ideas? Have tried resetting, have checked pressure. have tried power cycling... Nowt. HELP!