ariston boiler heating

Thank you for taking the time to read this. We have recently moved into a new house which has an Ariston Clas HE system evo boiler (without clock) operated by a Honeywell ST9400C timing control with separate walled mounted thermostat. Each of the three items appear to be operating correctly...

Hi! I just moved to a new property and I cannot make the boiler to fire up the heating. I have a CLAS HE Ariston boiler. It was turned off when I moved. I turned it on, turned on the hot water, and all is good and working great. But today I wanted to test the heating, and the boiler won't come...