If this is a 15 CFM blower it should not put out a significant amount of heat. The major problem is the additional cubic feet demand placed on the refrigerator. Try to adjust to maintain 38F liquid. The amount of insulation in the tower is spec. You can put thicker material inside but you will risk air flow problems at the tower. Carpet pad is a great idea. Be careful on how thick it is.
Scott Zuhse, Instructor
Micro Matic Dispense Institute