I arrived for a non member no cool call. I inspected the system and found the drain line to be stopped up causing the overflowing switch to turn the system off. With the homeowners approval I removed the Ptrap on the positive pressures drain line and installed a straight drain. I blew out the drain line with nitrogen both ways into and out of the evaporator coil. Once the system was drained out and the unit cycling on I checked the blower motor and condenser operation and found no major issues at this time. I did find the contactor to start to blacken and pit and recommended to have this component replaced as a preventative repair at this time. We decided to let the system run for the summer.