No heating, ferroli, errors not listed?

I've got a ferroli Optimax HE plus 31 c
It's stopped heating water.
Tried resetting it and I've seen 3 different errors on screen but none are in the manual.

Sometimes it says d1.
Sometimes says --
Sometimes says a funny digit which looks like an E then 5 (but the E has the top stick missing)

The pressure is ok. And i have a prepay meter that is in credit.