There are times when the attempt to do something positive can result in something unexpected or unforeseen. The annual increase in the number of hard-start kits being added to air conditioners is a perfect example. Hard-start kits are being installed by contractors for a variety of reasons: extending the life of an old compressor, reducing starting amperage, and lowering the load on the utilities; etc. 

Utilizing a failed (that is, “open”) motor-run capacitor as the basis for our “Destructive-Analysis” experiments led directly to the failure of a number of our test compressors.  That is, once started, a compressor will run without a motor-run capacitor.  Compressors were never meant to operate without a motor-run capacitor. The problem will occur because the hard-start Kit will briefly replace the failed motor-run capacitor thereby allowing the compressor to restart.  In our experiments, we’ve seen the compressor quickly overheat, with surface temperatures reaching as high as 213.8­ ºF and refrigerant pressures as high as 700psi.  While the compressor’s own internal protective devices attempt to protect the compressor, the repeated restarts are what destroys it.