Why would my freezer suddenly start working again?

[Dieu]

Hi. I'm just curious about something really. I have a relatively old Candy fridge-freezer. It's half and half, with the freezer part on the bottom. Just in time for lockdown, the freezer part wasn't working. I had to throw away all my defrosted food. The fridge was still working fine. Freezer sat empty for a couple of weeks, but lo and behold, now appears to be functioning. I thought it felt colder, so tested it by making ice-cubes and sticking a pizza in there. Both rock hard!
I'm reluctant to go out and buy more freezer food, without understanding why this happened. Or why the delay before working again. The fridge now also has a thin icy layer at the back, so it seems cooler all round
I haven't messed with the temperature (it's a very basic 1-5 control dial), but did a couple of weeks ago clean the condenser coils at the back of the unit.
Thanks!

No expert, but sounds like maybe the controls/wiring is a bit dodgy? I’d be a bit worried about it causing a fire, but I’m paranoid about such things and have to go round switching stuff off before I go to bed.

I suspect the compressor may have frozen and stopped working. The ice has now defrosted enabling it to restart. Is there plenty of ventilation round it?

My undercounter freezer stopped working - I did some research and thought that might be the issue. Unplugged it for about 12 (suggestion was 36 hours I think) and it worked again - for about 6 months. Did a full 36 hours defrost about a year ago and it is still working. I do suspect there is insufficient ventilation as it is under counter however I have since moved and the new owners, who have the freezer, report no problems. They are having a new kitchen and will be replacing it anyway soon.

Thanks both! Hmm, interesting question about the space around it. It is fairly tight I guess, as my kitchen is small. In fact, I was dreading the whole thing packing in, as removal would be impossible during lockdown. I reckon the kitchen was originally fitted around the fridge-freezer! (predecessors left it behind). I'll try moving the back of it a bit further out from the wall.

I had the same. It's to do with the frost free function. I left it for a day to actually defrost as the back, but it kept doing the same. I wouldn't trust it.

My old freezer used to do this, about once a year. The fins in the back, behind the metal get encased with ice so it thinks its cold. I used to turn it off and lift the metal at the back and defrost with a hair dryer. I could have left it a couple days to defrost itself but could put stuff back in quicker using the hair dryer.
I had to take the screws out the inside back metal plate and pull it up enough to expose the fins.