Domusa boiler "Error 81"

[sprinkler]

My new Domusa oil boiler MCF DXV shows "error 81" on the remote programmer E20. And the manual explains that it is a problem of "EEPROM" or adjustment required in the Accumulator regulator.
When the technician came to start up the boiler, he didnt know what the error meant.
Some problems I have: when I set the programmer to reduce the temp of hot water to 22 C, it usually just returns by itself to 50 C.
Or when I try to turn off all hot water completely, just leaving the boiler prepared to turn on at 5C for the coldest winter months (when the house may be empty), the programmer still turns on the hot water anyway. So I can't actually turn off the hot water to the taps. I don't know if these faults are connected with the "error 81" message...any help greatly appreciated.

[sprinkler]

Re: Domusa boiler "Error 81"

I did manage to get rid of the "error 81" message by pressing reset etc and restoring EEPROM settings, BUT I still have the same problems with the HW. Now the programmer is set only to turn on the boiler when the temp. drops to 5 C, with the hot water switched off. But in reality the HW continues and I can find no way to program it to stay off, though the programmer manual says that the HW can be turned off. Seems that there must be some communication problem between the programmer and the boiler?