Upright Freezer will not cool. Otherwise all components work.

Description of Problem:

Upright freezer will only cool to 12C.

• Compressor is working properly
• Defrost Timer is working properly
• Defrost heater is working properly
• The start capacitor is working properly and has been checked to be within tolerance (11.83µF, spec 12µF +-5%)

Can the cooling system get blocked / plugged? It is as if the coolant is not flowing properly. The input side of the evaporator core is building frost but inches away it isn't even cold. After 8 hours without a defrost cycle I would expect the entire evaporator coil to be covered in a light layer of frost. It seems like only the area directly adjacent to the incoming coolant is cold and this area seems to be creeping across the coil very slowly but to a maximum of only inches. The evaporator coil is still warm on the right side where the coolant should be leaving to the cooling circuit. The outside of the unit is cool to the touch where it should be warm.

The input side is -18C right where the coolant enters the evaporator coil. The other side is 12C. This is after 9 hours. No defrost cycle. It will not get any colder. The coolant doesn't seem to be flowing at all.

If there is a way that the cooling system can become blocked/plugged, is there a way to backflush or otherwise dislodge the blockage? I am not a refrigerator technician.

Thanks.