Box Temperature Too High

What is the temperature control setting?Control set too highReset control
Is the evaporator dirty or iced up?Iced or plugged coilDefrost or clean
Have you checked the refrigerant level?Refrigerant shortage. Air in systemRepair leak and recharge
Have you checked the expansion valve?Expansion valve Superheat set too highLower Superheat setting
 Expansion valve too smallRaise suction pressure with larger valve
 Plugged expansion valve or retainerClean or replace
Is system capacity sufficient for product load?Product load greater than system capacityAdd additional units or replace
Is evaporator properly sized for product load?Evaporator too smallAdd evaporator surface or replace
Are refrigerant lines properly sized?Refrigerant lines mis-sizedReplace with properly sized lines
Are there any restrictions?Refrigerant lines restrictedClear restriction