When arriving at the customers house thermostat on to AC, then I proceeded to put my gauges on the AC unit, and I found a pressure are low. The system is about 4 pounds of R22. And customer had asked if I could get the water out of the drain pan because water was leaking on the floor. I went to get water out of the call pan to find its draining good. But I did see rust and corrosion all over the coil fittings.