Top compartment thaws

[The Claw]

I am a Novice trying to diagnose a freezer fault.
I returned from a 3 week holiday to find the icecream melted in the top compartment of my upright F&P frost-free freezer. A frozen bottle of water was also starting to melt around the edges.
The freezer is 3 years old.
The motor was off so I turned the adjustable thermostat from 5 to 7 and it restarted and ran for a while. I checked later and the motor was off again.
The unit also has an 8hr clock which I guess performs the frostfree function.
I bypassed the thermostat and have run the unit for 36 hours but the icecream is still melted and top compartment is only 1 degrees celcius. Bottom draw contains a bag with icecubes which shows no sign of melting. Temp is -2 deg there. I did not measure temp previously because I only just found the thermometer.
Can someone please explain why the thermostat was off before but bypassing it has not fixed the problem?

[The Claw]

I bypassed the thermostat and have run the unit for 36 hours but the icecream is still melted and top compartment is only 1 degrees celcius. Bottom draw contains a bag with icecubes which shows no sign of melting. Temp is -2 deg there. I did not measure temp previously because I only just found the thermometer.
Can someone please explain why the thermostat was off before but bypassing it has not fixed the problem?

48 hours later and still not refrozen.
Can anyone explain to me how the 8-hour clock performs the frost-free operation?

[Chunk]

Hi Theclaw

The 8 hour clock would probably time out to defrost every 8 hours.
My own fridge/freezer has a defrost cycle every 8 hours.

Not coming from a domestic background i`m probably not the best person on this forum on the subject.

As for your other problem it could be that your compressor is faulty and when you first checked the unit was on defrost thus holding off the thermostat.you linking it out proves there is a fault elsewhere.

Ice will stay frozen below 0 degrees as water freezes at 0.

I would suggest to start with,switch freezer off for a day to cool down and restart when it is cool.
Check compressor area for anything that can cause overheating.I dont know what type of cabinet you have as you have not given us the information but this way would be a good way to start.

[The Claw]

I just read a good description of the operation of the defrost cycle at vvv.appliance411.com/faq/howdefrostworks.shtml
Also my freezer just completed a defrost cycle and restarted but no water dripped out. This could mean that the defrost heater is broken. The thermostat issue is less clear. Unless I made a stupid mistake, it must be faulty also.

[The Claw]

I ripped-out all the food, the drawers and the internal back of the freezer. I found the radiator badly iced-up. Defrosted with a hose, put it all back including thermostat, and now it is working normally.
My only explanation for the thermostat malfunction was that perhaps it too was joined by ice to the cold radiator and hence was tripping off.
Probably a blown defrost heater. I'll look at it in a few weeks.