ᐅ Underfloor heating on the first floor is no longer working.

Hello, we need some help.
The underfloor heating on the first floor is no longer heating, but it still works in the ground floor and basement.
The pressure gauge shows 1.2 bar. The heating system was serviced at the beginning of the year. I suspect that our 5-year-old godchild might have adjusted some valves.

I noticed that when I turn the red valves in the ground floor to a vertical position, the supply pipe on the first floor gets warm, but that’s all.
Could it be that something is incorrectly adjusted?

See pictures.

We have had this twice in two years; both times it was the small extra fine fuse...

P.S. Your pictures are not visible...

Here are the pictures. K stands for basement, EG for ground floor, 1 ET for first floor. As mentioned, the heating runs on the ground floor as well when in the basement. On the first floor, the supply line only heats up if I turn the red valves on the ground floor to vertical, but the floor remains cold.

Matthew03 schrieb:

We’ve had this happen twice in two years; both times it was the small extra fine fuse...

P.S. Your pictures are not visible...

Which one do you mean, the actuator?

Vertical means closed. So they would all have to be positioned horizontally. Is there enough water in the system?

Mycraft schrieb:

Vertical means closed. So they would all have to be horizontal. Is there enough water in the system?

Yes, when I position the two red valves on the ground floor horizontally, the supply line on the first floor doesn’t even heat up.

I think there is enough water in the system. It was serviced in March, and at least 1.2 is shown— is that the water level? Unfortunately, I wasn’t there during the service, and I don’t know if it was vented.