Delonghi Primadonna S- Delux- ECAM 26.455 -Heating Issues
These machines are coming into the workshop every other day, with the same issue. And we receive a lot of phone calls about the same old issues. This machines cohort are 10 years old now, so their appearance in our workshop is more a function of their age than any inherent design issues. The notes below answer some of the common questions.Yes they have 2 thermoblocks. The flash boiler sits just above the Main Coffee Thermoblock. However the main thermoblock is housed in a black casing so its not obvious. But you will find it, its held in place by 3 screws.


Heating issues usually present as the famous General Alarm. If the machine gets through to the rinse and then hangs on heating before timing out to General alarm, then its the flash boiler at fault. If it immediately times out to general alarm before running the rinse cycle, then the main boiler has an issue.

The good news is these machines often blow thermal fuses. The bad news is there is often a reason for the blown fuse.
More good news, the main thermoblock on the coffee side is not usually the issue, the flash boilers often go open circuit. this is good news because they are much easier to replace. The coffee boiler has the thermal fuses mounted behind it. These fuses are difficult to get at.
If you find both thermal fuses are open circuit, then you certainly have an issue with the Triac on the board or an NTC sensor. Usually its a Triac that has locked on and cooked the thermoblock and the thermal fuses. Sometimes it is an NTC sensor at fault. Its best practice to replace the Triac and the NTC sensor to be sure.