FRIGIDAIRE UPRIGHT FREEZER ONLY 2 BOTTOM SHELFS FREEZING

If Door seals are sealing properly, it’s probably a freon or compressor related problem

you may have ab ad fan inside the cooler and all of the cold air is staying at the bottom. Also there may be bad insulation at the top and there may be warm air up there.

Just had this issue. Freezer is packed usually & suspected airflow. Emptied bottom 2 shelves & vent strip was solid frost. Bottom 2 shelves were filled w/ solid roasts & other solid large items. Used blowdryer & currently waiting to see if it begins freezing top shelf.

http://manuals.frigidaire.com/prodinfo_pdf/StCloud/216802800en.pdf
Your unit is not self defrosting so I would suggest you do a manual defrost and see if it corrects the problem.
Also make sure that you have good air flow across the compressor.

keep the door closed by all means any small opening can leave the freezer start to defrost slowly without you knowing it

Check your circulatation fan. It may be stuck. Keep me informed The Raz Shack

Check the freezer back wall for snow or frost.If it's there you have a defrost problem.

Sounds like a defrost system problem. Could be related to defrost timer, heaters or defrost thermostat. Have it serviced.

If your freezer is six years old the compressor warranty is also over. Sounds as though the system has lost its refrigerant charge. A refrigerant leak in these smaller units is difficult to locate and somewhat expensive to repair. Your choice.

DR....let's go down the list:

First is freeze up. This happens when too much humidity gets into the unit from the air and forms ice on the coils. Defrost the unit using warm air or leave it open and off for two days.

Problems that cause this: high humidity, 'window shopping', unit not left closed or bad gasket. If the gasket looks damaged, it will need to be replaced. Gaskets that have accumulated dirt don't seal. Use a mild cleaner to fix this. If you have doubts about an area where the seal is questionable...use a sheet of paper about 2-3 inches wide, close the door and pull it through. No resistance indicates a poor seal.

Make sure you clean out the condenser...the coils where the heat is rejected by the unit.

It is possible that you have refrigerant or defrost timer issues. To check for low refrigerant, start the unit after defrosting it. Note that the larger pipe attached to the big black thing....the compressor...will start to frost. It should then start to form ice while the unit is running...about 5 minutes. If the frost stays and the pipe is not REALLY cold, you have a problem with refrigerant. Sealed units are warranted for 5 years. Defrost timer issues are best left to a tech.