I'm the super of a 93 unit apts and one of the apt the heat won't shut off we use a motorize valves in the apt connected to thermostate I just pput the motorized valve on its new but the hot water still flowing through the pipes.if something blocking it and keeping the valve from closing what can I do

Start by checking to see if the valve motor is getting a signal from the stat. I doubt that there would be anything solid in the piping that would lodge a valve open.