I'm using an old medium sized forced air fridge with a separate freezer compartment as my cheese cave.
While I now live in US, it's 220 volt/50 Hz from when my family and I lived in a different country where in it's previous life it was a drinks fridge
As the thermostat won't allow it to go warm enough, I have it on an external analog Johnson Control thermostat
. And, as it is 220 volt I have it on a 110>220 volt transformer, so the fridge plugs into the transformer and the transformer plugs into the Johnson Controls external thermostat which plugs into the wall socket in our garage. Yep 50 Hz motor on 60Hz system is not good but I figure use it until it dies and then I'll buy a new fridge.
Worked fine until 1 week ago when the temp gauge inside read ambient 72F temp, I checked the freezer and cold, so I thought maybe the temp gauge was wonky. Checked again two days ago, still warm and couple of my cheeses got moldy, so in emergency, moved them to household cold fridge.
Problem could be the controller or the fridge, but freezer still getting cold, so to try and "repair", pulled back wall off of freezer and surprise, all frozen up, found problem!
The back wall has on it's backside a diverter that diverts air from cooling coils past fan and down into lower fridge compartment.
Shut off unit for one day, ice all melted, started unit with back freezer wall off so could see in future if problem starting again, but fridge didn't get cold. Duh, needs back wall with diverter otherwise just the freezer compartment gets cold. Replaced back wall and fridge now cheese cave 55F again
My problem is why did this happen and how to stop it in future?
I think I had the the fridge dial set to low 1, which reduces the air flow from the freezer to the fridge, maybe that was making the cooling system work extra hard to get the fridge cold, so I've now set it to max? Or maybe the freezer is not go through it's normal auto defrost mode as on external thermostat - timer? But no frost in freezer, just behind back wall on cooling coils.
Any ideas appreciated, John.