Need -20 degrees Celsius...Will this brand get there?

no rule of thumb
maybe if you got a different thermostat that has a lower setting than standard
however as upright freezers are very bad freezers compared to chest type freezers the lowest reading will be around the -35 degrees C
Why very bad -- every time you open the door you dump 20 degrees out onto the floor and the temp difference is more pronounced than opening the lid of a chest unit which keeps all of the cold in the unit
remember the colder the setting the more the compressor is working

A flashing red light on a tall freezer indicates that the appliance has detected a temperature alarm, and the temperature inside the freezer has likely dropped below the desired range. A temperature of -6 degrees Celsius is much lower than the recommended temperature for a freezer (-18 degrees Celsius), which can cause frozen food to become damaged or spoiled.
To resolve the issue, you should first check the freezer's manual for troubleshooting tips and recommended actions. In general, you may need to adjust the thermostat to a higher temperature, remove any obstructions to airflow, or defrost the freezer if ice buildup is blocking the evaporator coils. If the issue persists, you should contact a qualified technician to diagnose and repair the freezer.

Hi,

Best way I can answer this is to purchase the right equipment for the job. A domestic freezer is not designed to work like that, although it may get there in temp it won't hold it. Recovery is slower then the industrial unit you seek. Domestic unit warranties are void if used for commercial settings (i.e. lunch rooms, offices, lab's, etc...) I wish I had a better answer for you but if you need a specific temperature get the correct equipment for the job. Good Luck

I’m happy to help further over the phone at https://www.6ya.com/expert/gere_bf68e6055dd61249

This is true of all HVAC type systems. The condensor releases heat from the expansion of the coolant. As long as the temperature is lower than the exchanged heat then there is no impact to efficiency.

The hot sides is normal, this is how they expel the heat from inside the freezer, sometimes it may help to use a fan to help cool. Also make sure there is about 12" of room around all sides of the freezer .

5.5 Cu. Ft. Chest Freezer Click to Enlarge Lowest price:$179.00Description:
Food storage will be a snap with this roomy 5.5 cu. ft. chest freezer, featuring up-front temperature control, storage basket and defrost water drain.

Brand: Magic Chef
Category:
Appliances > Refrigerators & Freezers > Freezers > Chest
UPC: 665679002023
Model Number: MCCF5WBX

Hi,
Please check : - Your door ( gasket /seals, small air leaks) - Refrigerant level - Temperature sensor for failed
Regards,

In short you possibly have a gas blockage or a leak in the system and need a Tech. with gauges and testing equiptment to confirm.

Correct temperature for residential freezer for food is zero degrees Fahrenheit

Big...this is likely normal. I'm not sure where you're measuring that temp from. If it is the fan outlet, this is possible. The fact that the unit is staying below 5 degrees means that it is within spec. You do have a warranty. Ask Sears to come on in and check it out.

Your 'duty cycle'...that amount of time that the compressor is on should be about 20% of a unit of time...say 25 minutes out of 2 hours. Is that about right? If so, enjoy your ice cream.