The freezer side of the unit will freeze until it freezes over and will no longer keep the freezer frozen. The freezer then has to be defrosted so it can freeze again.

Check for ice / frosting inside the freezer .... If present you probably have a defrost problem.... This causes the freezer coil to ice up and block the air flow ... the causes could be a bad defrost heater , defrost timer, defrost sensors, or control board. Also make sure that the condenser coil is clean. remove ALL dust with a vacuum and a coil brush .the coil is located either on the bottom or on the back side of the unit... You didn't give the Make and model #

Try to defrost the freezer and see if the air valve opens and closes properly if all of that works then there is a problem with the fan that moves the cold air into the refirgerator

Check temp. in freezer shoud be 0 to -5 Deg. Check condensor if dirty clean some units had a recall on diers cap.tube to far in dier also check for ice on back wall if icedup check defrost heater and defrost timer check evap. fan make sure it's turning.

THE RED WARNING LIGHT KEEPS COMING ON AND I HAVE TO KEEP PRESSING THE FAST FREEZE BUTTON, THIS IS EVERY FEW DAYS. IF I DONT NOTICE ALL THE FOOD DEFROSTS!

Check the vents in the fridge side and close a little if you can. On the freezer side just for good measure>>>>
Is your circulating fan working?
Sometimes they stick and need a shot of WD 40 and then work
it back and forth a little until it wants to take off again. Keep me informed
and PLEASE give a Thumbs Up for the effort. The Raz Shack

Check rear wall of freezer by feel for frost. Heavy, even frost indicates likely problem in the defrost system. Unplug unit. Defrost heater (in freezer behind rear wall panel), defrost thermostat (same area-must be checked at freezer temperature) or Defrost timer-located lower back outside of unit. Near compressor. Do continuity test on heater and defrost thermostat and if they show continuity (good), replace defrost timer. If not, replace the one that tests bad.

Defrost coils fully. Reassemble.

Please let me know if I have helped with comments and rating.

Refrigerator will work about 7-10 days after being defrosted until thick frost builds up again cutting off air flow to both compartments

In most cases, an evap that freezes up is either an air flow problem or no defrost cycle. Older Hobarts have mechanical defrost time clocks. It could be locked up i.e., not running so no defrost cycle.
It could be coming out of defrost too early because the sensor that monitors the evap temp is not working properly.
The door could not be closing. If left cracked open, it will freeze up every time as unit never hits temp., keeps unit running. Warm air is seeping in and the moisture freezes on evap.
Lastly, the defrost heater(s) may not be working. Burned out, shorted, broken wire, etc.

Good luck and hope this helps.

Causes:

High humidity in the immediate area causing condensation to freeze at the door opening

A frozen defrost drain line not allowing water to drain off when the unit is in defrost

A bad door gasket causing an air leak

Some freezers have a heated perimeter to reduce condensation. If the stop working, moisture can accumulate arounf the door perimeter and freeze.

Leaving the door open too long or something obstructing the door

Your best bet is to start in the middle. Guesstimate and let it run. The test is to see if water freezes solid in 6-8 hours. If not, you can turn about 1/4 turn or less. Then you can try hamburger meat which a lower freezing temp and see if it gets solid. Your perishable items should be put somewhere else until you are ready. At least the water frozen will keep the meat safe from bacteria growth or spoilage. Let me know how you do.

thius suggests the defrost system not working and the defrost drain blocked. take off the back panel inside the freezer, melt off excessive ice and free the drain at the bottom with hot water and patience