Underfloor heating not adjustable

I live in an apartment of a multi-family house (built in the early 2000s). My problem is that I cannot regulate the underfloor heating myself. It seems to depend on the outside temperature. In summer, little to no heating, in winter quite strong. The controllers in my apartment are permanently set to the lowest level. Nevertheless, it is generally just too warm in the apartment, so I often tilt the window or similar to regulate the temperature.

Attached is a photo of the underfloor heating



I had opened and closed the red valves to completely turn off the heating in summer, but this had no effect.

Do you have any idea why I cannot regulate the underfloor heating and what could possibly be done about it?

Thank you.

Nevertheless, it is generally simply too warm in the apartment

What does that mean? How many degrees warm is it?

The red attachments are the actuators which are connected to your thermostats in the rooms. If they are not properly mounted, they do not work and may simply remain permanently open. That would also explain why it is too warm.

Turning them around might have contributed to this as well.

What does the landlord say or is it property?

Inform the janitor, if every tenant fiddles around by themselves, chaos arises, it is a whole system. When 80% of the tenants have turned it off, there is a sauna in the remaining 20%.

The landlord said back then that I could turn the red handles at the bottom right to completely shut off the heating at least in summer. But it still continues to heat.

I will get in touch with the janitor to see if he knows anything about it, and if not, call a craftsman to have a quick look to see if it is due to the settings or something similar.

The landlord is a jerk; every good heating system should turn off in summer, if only for economic reasons.

Mycraft said the rest: check if the actuators are loose and if maybe only a fuse is blown; otherwise, the janitor will surely help, and it’s your money that you’re wasting.