All, I added a Hard Start Cap to my units. It is completely safe and will not hurt your units. It helps them start. When the compressor starts to pull current voltage sags and these babies are basically a storage device for voltage and prevents the sag (lights may flutter in coach, just a example of a sag). You can go to any HVAC store and ask them a knowledgable guy will concur. You know how RV parks power might be less than perfect, these help the compressor get started.......... You can leave the stock cap in and just wire thin in parallel, instructions are included.