Abstract: A method and apparatus for testing cooling units used in computers is presented. Testing of such cooling systems increases the reliability thereof, which in turn increases the reliability of the computers utilizing these cooling systems. The cooling system tester comprises a test frame which supports a plurality of evaporators, associated modular cooling units (units under test) and associated fan or blower assemblies. A heating element is attached to each of these evaporators to act as a heat load for the corresponding modular cooling unit, i.e., to simulate the heat load of an actual computer. The heat output of the heating elements are controlled by a computer. The power supplied to the modular cooling units is also regulated (controlled) by the computer. A program in the computer runs a test on each of the modular cooling units. The program checks for user input and the installation of a modular cooling unit.