Why do you need a hard start kit?

some reciprocating and scroll type compressors, especially with age, may need help starting often when under a load, or when a short cycle occurs. Refrigerant pressures between the high and low sides, when operating, are often 100 psi and more apart. When the system does cycle the refrigerant pressures tend to equalize and this is when the starting load is at a minimum. When a compressor tries to start on a load, or when pressures have not had a chance to equalize, it may shut down on an internal overload, or may even trip a breaker while attempting to start. A hard start assist often will help by momentarily boosting the voltage to the compressor start winding while attempting to start.