Tiles in the utility room under the technology shortly after screed installation

Hello. Our construction contractor said that the screed would be installed now. After 3 days, tiles are supposed to be laid on the still wet screed in the areas where [Technik] is located. This would allow the heating engineer and the electrician to continue working and to install the gas heating, hot water tank, and controlled residential ventilation. So far, the tilers have advised against this. One said it was not necessary, as it was only about the early start of the screed drying program and for this the gas heating (wall-mounted) is sufficient. The 300L hot water tank can be placed on the floor later, after the screed drying program has finished. The tiler's primary concern is the tile laying pattern, since we will have the same tiles in the utility room as in the kitchen, living room, dining area, and hallway. Do you have an opinion on this?

The laying pattern can also be determined and planned in advance, but three days (without drying program) seem clearly too short to me for laying. At our place, the gas boiler was hung up first, then dried, and sometime later the hot water tank was installed. (By the way, the ventilation system is usually mounted on the wall.)

The 300L hot water storage tank can be placed on the floor later, after the screed drying program has run through.

Yes, that is also correct. You can also run the screed drying program without completing it.

Our tiler said back then, either the screed is properly dry or properly wet...

I would have the tiles installed in that specific area beforehand. Better that way than having to patch them onto the hot water tank afterwards. Nobody will dismantle it for that!

He will simply be delivered and connected only when the time is right. No one has to piece anything together.

We have only just received our tiles and technology, after 6 weeks of screed drying (3 weeks it was left as is and 3 weeks it was heated up) a mobile heater was used with us. But we also have a heat pump.