Upon my arrival I checked into the concerns of the upstairs system freezing over. Performing my diagnostics I found that the voltage enhancement system failed preventing the air movement system to come on and move air across the coil. I spoke with the home owner about concerns and he approved to get the system back operational today. I performed the approved repairs then ran a performance and safety testing finding the system running the best it can given its age. Upstairs unit does need a new air filter installed.