We should use the term refrigerant unless we really mean DuPont brand refrigerants. R efrigerant in critical to the operation of a system. In addition to the obvious need for cooling whatever properly, it cools parts of the compressor and moves lubricating oil to the compressor. Too little, and the system can be damaged and won't work properly. Too much refrigerant can be even a greater problem.
Excess refrigerant washes the oil right off of critical compressor parts.
Before we start adding refrigerant to something, let's check out some other problem areas first. W hatever else we do later, the first thing is to make sure the machine is clean. Dirt just mucks up all kinds of machinery. Air flow is critical, too. Any belts, filters, coils and blowers must be clean and working properly.