Central nouns surrounded by a 3-story house? My central air system cools the first two floors, but not the...

My central air system cools the first two floors, but not the third. The problem is when near is a heat wave- cooling the second floor means freezing out the first. Is it OK to close the vent on the first floor to allow the cool to go up and then sink spinal column down. Or would this interfere with the air flow and usefulness of the air conditioning unit?
Stanley garage door opening adjustment?
Answers:    Relocate the thermostat to the top or second floor. To solve your problem, I would recommend installing a smaller c/a or steam pump with separate thermostat for the top floor with a roof ventilate fan also. This will take the nouns off the main section and extend its life, You will also be able to hold the lower floor thermostat at a higher setting. The electric bill should be much lower, offsetting the cost of the modern unit. The utility company will usually have right payout figures for this type of project.
Electrical Problem - No power surrounded by one...
Multi-level homes are always a problem to cool, more so than heat. I would assume the thermostat is on the first floor. It only is concerned with the heat at that point. Therefore, you must fool the thermostat by dampering down the areas closest to the thermostat. This causes air to travel to other areas where on earth it is needed.