khalid - Not much advice to give here apart from what you already found the hard way. My Elizabeth is over 3 years old and it was never descaled and using it has been no different from when it was brand new. But then again I always added non-scaling water to the machine so I know that I don’t need to descale ever.
When you say that the problem is in the steam boiler… It might be, but the brew boiler is likely to be full of it, due to two reasons:
- The brew boiler heats up to 130C during warm up. The hotter the water, the more scale you’ll have;
- When you use the hot water tap, or steam pre-infusion, the brew boiler fills with water from the steam boiler - which, in your case, is full of limescale.
If there’s limescale in the cross-fitting, then that eventually ended up back in the tank.
Backflusing with detergent will do very little to remove limescale or clean the brew path on this machine. As you have full access to the dispersion plate and shower screen, you might see the extent of limescale and how dirty it is there. Yes, you have successfully cleaned the group solenoid, but not much more than that. And that’s one of the reasons backflushing is important in this machine - you don’t want the brew group solenoid clogged up.
You should not screw things back in tight. Think about the next time you’ll need to remove them. If they are too tight, you will likely deform any gasket/seal, and risk breaking it next time you need it to do maintenance again. There are plenty of videos on Lelit Insider Youtube channel (You say in your post you watched them), showing how to remove the fittings and put them back together nicely. One of the golden rules of good maintenance and longevity is to never screw things in too tight. If you have, you are likely doing something wrong.
I’m assuming prior to buying this machine you read DavecUK’s review of the Elizabeth. You haven’t… Then it’s too bad :-) - But I will quote one sentence from that excellent review (https://coffeeequipmentreviews.wordpress.com/2020/05/08/lelit-elizabeth/):
Quote from “Maintenance and Pro Tips” section: “The first thing I want to say about descaling is…don’t.”
If you haven’t read the review, specially the Maintenance and Pro Tips section, I’d strongly recommend you do.
Your machine looks really nice inside, looks like there were no leaks.
Good luck with the descaling.