Baseboard heating too hot

Lolz

   I have searched the Internet and have no clear answers to this, So hopefully someone can help me out.   I live in Edmonton Alberta, where the weather shifts from hot to cold often. I live on a second floor apartment , only one person beside me and one below. It's an older building and has baseboard heating, water not electric.   

    I went to bed last night and had the windows open a bit, when I woke up at 5 am I was boiling. I checked and the temperature was +21 in my apartment. My thermostat is set to 0 (so off)  , so obviously it's a dummy thermostat or something is broken.  All last winter I had my windows open and it was still hot in my unit.   It's controlled by a boiler downstairs 

   I have closed the fins already, the pipes are HOT to the touch. Its not even fall yet. How do I reduce heat  ? would putting tin foil in front of opening work ? I can't remove the covers at all, they are the old school cast iron ones (I've tried ) . Any options to help or is there something very wrong with my units system ?

 I rent so no option to add anything 

mattmia2

If the baseboard is cast iron then the whole thing is the heating element, it is just a big chunk of cast iron that gets filled with hot water. Blocking up the slots in it will reduce the output a little bit but it works a lot more like an old floor standing type cast iron radiator where the whole surface is heating the space.

That baseboard looks something like this:

https://newyorksalvage.net/products/antique-hot-water-base-board-heat-36-section-cast-iron-old-vtg-base-ray-372-18p

I would suggest you get whoever is responsible for the boiler to figure out what is wrong with your control. The thermostat likely controls some sort of zone valve which either has got stuck open or it is a normally open style valve and the controls have failed. That valve may be by the boiler or somewhere where the piping enters your apartment. What kind of thermostat is it, is it electronic or mechanical?

STEVEusaPA

Tell the landlord to fix it, unless he’s not paying for heat, in which case he doesn’t care.
It’s a simple fix in that it worked correctly once.
Didn’t necessarily say easy or cheap, but it’s a pretty common problem that just requires some troubleshooting by a qualified tech.

EBEBRATT-Ed

And it will be cheaper to fix than to waste all that fuel