Something as simple as a prominent banner on the packaging and start up info would help: "Download Lelit's Official User Manual here." By the time a purchase decision is made and the machine finally arrives, we've spent countless hours reading and watching sales-oriented glosses, posts, youtubes etc. Some are useful but typically don't address fine-grained details nor is the info easily retrievable as to the source.

With my printout I could reference the OP's question. Sort of. Under the heading "Steam boiler enabling/disabling," I find that "E" does not mean "error" but "economy mode." which is (only?) entered by disabling the steam boiler. This is probably different from the previously mentioned programmable power saving mode, but I'm not sure of that. Read on. . .