Performed AC diagnostic on 2014 York package unit. Upon my diagnostic employee complained that it seemed like AC was not turning on up on roof And will either maintain either 77 or go up in temperature when set to 68°. Upon further inspection measured refrigerant pressures on package unit and found that system was low on 410 a charge added in 3 pounds of charge And changed dirty restricted Filter that was also causing temperature Issues. Measure temperature split and found that supply was 59° when indoor was 77 Giving at least an 18° split. Upon departure system is fully operational and cooling and employee states that there’s a big difference now. Also when I was leaving the lock broke to the door where the key is located as I was trying to put it back in so I taped it on there does need to be fixed.