Upon my arrival, I performed a six month check up on one straight, cool furnace system. Flush and treated the water remove system, washed the condenser coil using water, cleaned and treated the electrical cabinet, replaced the air filter then verified systems safety and performance. I found everything on the system operating within manufacture specifications at this time. During the evaluation I did find that the power protection at the indoor and outdoor units are no longer working. I went over my concerns with the customer and he approved HT4C. 10% was collected today and a return will be scheduled.