Frost build-up on the evaporator can be caused by extremely long cycles. Please Unplug the Unit until the ice melts.
reset the set point to a higher temperature
reset the fan speed to a higher value, and check if the cold side fans are running(after 1 minute delay).
In the case the fans are not operating see FANS or in case they are hardly spinning ( fan blades are visibly slow ) see CONTROLLERS.
If the frost build-up continues, it may indicate the early stage of a refrigerant leak. This leak is a harmless vapor.
FROST ON THE COIL:
As with long compressor cycling, a slight build-up of ice or frost on the evaporator coil can be a temporary problem brought on by extreme ambient conditions. Follow the steps outlined in Long Cooling Cycles section. Try adjusting the Set-Temp upwards a degree or two, and see if there is any change in performance. If ice on the coil is a persistent problem, it may indicate the early stages of a refrigerant leak.
Request Warranty Service UNDER WARRANTY: (My unit is less than 1 year old (from the date of purchase). I have the Serial Number for my cooling unit and a copy of my dated bill of sale).
OUT OF WARRANTY: (I purchased my unit more than a year ago)
Options for service