Please note... I am not trying to argue with you by any means... I also am not trying to say the my way is right and your way is wrong.
How was the cold side getting too warm? What temperature did you have the hot side set at?
Most comercial rack systems I am familiar with are made for room temperatures of 77 - 82 degrees. Even if the room was at 82, the hot spot should have been throwing out so much heat that the cold side was too hot.