What Happened to my Fridge

[NBBrewer]

I received this fridge, cleared the drain, replaced the thermister and it seemed to work fine. Used it for bottle conditioning or could be a good kegerator for the camp. Now it does this(see attached graph).

Does anybody know what happened to my fridge?

 

[Dr_Jeff]

Freon Leak?
compressor crapping out?

 

[day_trippr]

That's an interesting plot. Even while struggling with the time base when I look at the plot it seems the cycle time is nearly unchanged across the plot which leads me to believe there's an instrumentation effect going on here. If the temperature was not "making goal" the plot would not show consistent cycling - the period would at least stretch if not effectively flat-line above goal.

Also, the period seems to be many hours - maybe 6 or more. Does that jibe with observations?

Cheers!

 

[sibelman]

Is there some kind of defrost cycle run amok?

 

[NBBrewer]

I believe the thermistor kicks on the defrost heater at around -2 or -3 celcius(my graph is slightly higher than actual temps and the thermometer can't be calibrated). Sooo it was hovering just at that temp with little to no ice buildup on the coils. 6 to eight hour cycles, then suddenly the temp only drops to slightly above where the thermistor kicks the defrost heater on and bingo you guessed it... ice starts to build up on the coil. It is an interesting fridge to say the least. My theory(one of several) is the drain is icing up and water is not able to drop out of the freezer after a while. This is a photo of the drain tube with a loop in it. I have a straight tube running down the the drain to test my theory.

 

[NBBrewer]

Weird fridge indeed. I have a few other fridges( I know... too many fridges... I have a therapist) and there almost seems to be no duty cycle.

That's an interesting plot. Even while struggling with the time base when I look at the plot it seems the cycle time is nearly unchanged across the plot which leads me to believe there's an instrumentation effect going on here. If the temperature was not "making goal" the plot would not show consistent cycling - the period would at least stretch if not effectively flat-line above goal.

Also, the period seems to be many hours - maybe 6 or more. Does that jibe with observations?

View attachment 744264

Cheers!