The thermostat or temp control may be bad causing the system to run non-stop.
There could also be a problem within the refrigerant cycle. Maybe a low charge, or no/faulty defrost cycle.
If the unit pulls to temp and continues to pull lower until it freezes, then the problem is most likely the temp control. If it will not pull to temp and the evaporator freezes up, then you may have a refrigerant charge issue.
Remember that the temp control on that unit is a coil temp sensor. It does not measure the air temp but rather the temp of the evaporator coil. So a larger air temp swing is expected, but the system should not be freezing up at all.
Answers & Comments
The thermostat or temp control may be bad causing the system to run non-stop.
There could also be a problem within the refrigerant cycle. Maybe a low charge, or no/faulty defrost cycle.
If the unit pulls to temp and continues to pull lower until it freezes, then the problem is most likely the temp control. If it will not pull to temp and the evaporator freezes up, then you may have a refrigerant charge issue.
Remember that the temp control on that unit is a coil temp sensor. It does not measure the air temp but rather the temp of the evaporator coil. So a larger air temp swing is expected, but the system should not be freezing up at all.