Thanks for the input. I believe that would apply to electric type heating though. With no water to absorb the heat from the element, yes, they would very quickly burn out.
Just my 2 cents worth but if you are renting, why not make the landlord fix it? Also, is this a true boiler system with steam or just hot water?Also I would think there would be some sort of trap/filter/screen in the system. If there is a calcium buildup in the pipes I doubt simply flushing will clean it out.