Upon arrival to scheduled multi system maintenance (4) I was shown to 3 A/H units located in the attic above the master bedroom closet. Immediately pulled off panel doors to inspect all electrical components connections, collect amp draw/voltage readings off equipment, and check the evap coil for cleanliness. Evaporator coils were clean, but significantly rusted. This could possibly be an issue down the road. All electrical components connections were secure and all amp draw/voltage readings were all within range of factory specifications. Collected temperature readings and had a 17-21 degree delta T temperature split in cooling on all 3 systems. Changed filters at the unit. All of these A/H units are equipped with Pure Air X UV light systems that are all fully functional at this time. There are separate air purification systems that were installed back in 2015 which are not in operating condition at this time. I do suggest having these replaced to ensure no loss of indoor air qu