Pulsacoil A class, no hot water at all

Hi, and good evening to you all. I just moved into a new flat, and I have an issue with the hot water - well, not an issue, it's just that there is no hot water at all

We tried adding some water to the tank over the boiler, but there was no change. The water (in both kitchen and bathroom) is slightly tepid, no more than that. We have the Economy 7 option, but not sure if it is active/working. I am attaching 2 pics so that you can understand better. Not being a native English speaker + having no clue on this matter is not helping explaining in details, I did my best

Thanks a lot for your time, this forum is brilliant!

Have a nice evening

Silvia