Freezer motor is running temp is 30 degrees - Frigidaire 11.6 cu. ft. / 328 liter Upright Freezer FFU12K1CW

Defrost cycle usually comes on after about 7 hours. If it is happening every 30 minutes or so, the defrost timer is not working properly and your internal temperature will never have a chance to go down to zero as SOP.

When defrost cycle comes on, the compressor is automatically shut off and internal freezer temps can go up by close to 25 degrees or more. It is for this reason that commercial freezers do not have auto defrost - the latter extols a price, convenience at the price of higher average temps and less time to properly store foodstuffs in freezer.

You should be able to set the unit up to 30?F and still freeze some contents.

why yes there is. Generally speaking, the head pressure should be around the "ambient +30" rule.
That is, measure the entering air temp to the condenser, say 75 degrees. Now add 30 to that and get 105 degrees. Look at a P/T chart and see what the pressure is for that temp which is about 253 for R-404-A.
The evap on a freezer leads the load so, as a general rule, the evap temp is going to be around minus 10 degrees to get a 0 degree box. Coolers are different. So, the pressure for a minus 10 evap is around 25 or so. But the unit has to be close to operating temp. If the box is warm, naturally the pressure is higher. And what influences the pressure is whether or not it's a TXV or a cap tube system.
If a TXV and no receiver, charge by subcooling. If a receiver, fill by sight glass. If Cap tube, charge by superheat.
Hope that answers your question.

I would start there. If the thermostat has an off setting, turn it there and see if it goes off. If not, try turning it to it's warmest setting while the box is cold to see if it turns off. To test to see if the relay/ contactor is stuck/bad, kill power to the unit (Unplug or turn off breaker). Disconnect one wire to the thermostat. Restore power. If unit runs, bad relay/contactor. If unit does not run, I'd replace the thermostat. Make sure the sensing bulb of the thermostat is in the conditioned space of the box or in the return air (intake) side of the evap so it can sense the box temp.

Good day,
Manufacturers of freezers do not give the option of running the machine much above that temperature. Normal operating temperature for a freezer is about -2 to about 8 above F.
Otherwise people could accidentally set the temp too warm and cause a loss of food.
Some appliance parts houses carry universal thermostats that could possibly cover the temperature range your looking for, but 30 degrees is far to warm to preserve frozen food safely.

That noise is typical when the compresor is trying to start but it doesn't , it could be the condensing fan motor that doesn't work and the compresor goes off on overload ; a common problem with this compresors is the relay (mounted at the side of the compresor behind a black plastic cover) goes bad , this you can replace is about $20 , and if still the compresor won't start you will need to put another one and this is an expensive job.

If the temperature fluctuations occur (at least the ones to 20-30 degrees) at intervals of 6 hours or so then you are catching it in it's defrost mode which occurs on a timer. The timer shuts off everything except lights every 6 hours for an average of 20 minutes. This usually isn't enough to thaw things but I have seen it cause some crystale. Look closely at the back inside wall of the freezer for an accumulation of frost. If you see it there then you may have a defrost problem. Usually this is accompanied by steadily rising temperature in the freezer and fresh food secions both. The temps you listed (0to10) are fine. Good luck, AJ

I'll try to give you the "Readers Digest" version.
First, make sure there is no ice build up on the evap. Light frost is O.K. as long as it does not effect air flow. (Very Important). All fans need to be running. Again, an air flow thing. There should be some product in the box but not too close to the evap. Again, an air flow thing.
The expansion device can effect your pressures to some degree i.e. Cap tube vs. TXV.
As a general rule of thumb, which I use almost everyday when it comes to pressures:
Low side is based on the temp difference between evap temp and condition space in the box. In freezers, it is almost always 10 degrees. If the box is 0 degrees then the evap needs to be at a minus 10 degrees. That is a pressure for R-404A of 24.5 psi. This only holds true when the temp in the box is approching set temp. I would say, about +10 degrees. 0 Degrees for the evap for R-404A is 33.5 psi.
High side should be ambient temp +30 degrees and then convert to a pressure for the refrigerant.
Example: 75 degrees in the room, +30 degrees equals 105 degrees. Now 105 degrees converted to a R-404A pressure is 253 psi. This will get you very close to the desired high side pressure.
I would look at low side first to see if it is within reason. Don't let the high side get too high. Increases the compression ratio and overworks the compressor.
Your icing problem could be a defrost issue and not a refrigerant charge issue.

Good Luck and hope this gets you started.

I believe the FF would mean a thermistor has an open circuit . If so then the sensor would need to be replaced .You can ohm the sensor and at room temp it should be around 1100 ohms.

Always disconnect power before attempting to repair any electrical appliance

Check the evaporator coil for frost buildup on the back. Check for frost on the suction line, the biggest line returning to the compressor. If frost is evident at these places you have a defrost system problem. These systems have a defrost timer that defrosts the coil at preset times. Check the timer for proper operation by marking the position of the dial and check back to see if it changes. If it does not change position the timer motor is most likely bad. If the dial is not rotating automatically you can manually turn the dial in the direction of the arrow and put it through a defrost cycle.