my boiler is a ferroli optimax he31c ?

can you hear it rumbling every now and then as well if so its the circuit board .if your desperate try giving the front of boiler 3 sharp hits with bottom of fist blhs.if not ferroli will replace it

ferroli engineer
May 2010

Providing the main boiler display is working it will be the clock.
No CN means no communication between the boiler electronics and the timer
If the boiler display is working correctly then the timer will be at fault or the plug on connection onto it is loose.
Try unplugging and plugging it in again.
If the display is not showing any readings (numbers ect) then it is likely to be the control pcb.

acs
May 2010