Upon arrival unit was turned to cool but nothing was happening. The indoor fan was running but the cooling side of the rtu was not. Checked to mak sure I had proper voltage and I had proper voltage. I then hooked up my gauges and found my liquid side to be extremely high this can be caused by a dirty unit. Performed a AC precision tune up. Clean and tune up AC; cleaned condenser coil, checked all outdoor electrical components, tested indoor air flow, checked refrigerant levels, and tested overall AC operation. While checking my numbers again I determined the system to be low on charge. The repairs have been denied as of now. With the age and condition of this system, would potentially look at replacement.