My Avantco SS1FHC upright freezer cannot maintain a consistent temp. It seems to go into defrost several times a day and then the temp goes up with each defrost and doesn’t go down below 35.

SOURCE: Frigidaire upright not cooling

It sound like you had a freon leak, you REALLY need to get this checked by a tech. if you are leaking freon it can be dangerous.

SOURCE: Kenmore Upright Freezer Model 253.9239780 Temp alarm, Temp rising slowly

you have a refrigeration issue partner let her go 16 yrs. is good service you can replace it for 3 to 5 hundred the repair will be that IF you can find someone with the r-12. don't go for a top it off and go deal the food you lose is to expensive for that to be economical.

SOURCE: My freezer's defrost systems runs constantly

i dont think so i would look at the compressor kicking out on thermal overload or a faulty thermostat thermostats have two settings cut in cut out your cut in could be bad and not turning the compressor on till the temp reaches melting temps now if your hearing a click buzz then you need to look at the compressor and make sure the compressor fan is running but its not a defrost promblem

SOURCE: My woods upright freezer keeps

check your door seal, by closing the door on a strip of newspaper all round the seal. this fault is usually air getting inside the freezer, it rises to the top making thick ice or snow.

SOURCE: Sears Ken Elite upright freezer model no 25329082991 temp alarm

alarm should go off when freezer reaches minus 18c or lower.