On arrival, I spoke with homeowner who mentioned that over the weekend the system would run for a few minutes then shut off and then come back on a few minutes later and just repeat the cycle. I turned the thermostat on and checked over operation. During the run cycle, the system tripped off. I went back up into the attic and found that the water safety switch had tripped at the primary drain line. I was able to determine that the location of the clog was near the high line branch connection at the tailpiece of bathroom sink. I spoke to the homeowner and recommended we clean and clear all the gunk from the primary condensate line to return system back to full operation. He chose to have the drain cleared today. I flushed and treated the primary drain line, verified proper slope of drain for condensate removal and cycled high voltage power to system. Tested all systems and verified operation. Everything is working at this time.