It seems that this equipment has already been repaired and passed gas, check the amperage of consumption of the compressor that is not above the working amperage that says the label of the equipment, if it is above is that gas past. Also this fault is given by failure in the revolutions of the turbine of the evaporator, you have to verify if the bearings are well. You also have to check that the evaporator coil is not dirty and plugged. I hope you get these proposals.