Philosophical Defrost timer question

[Haywood]

I have installed a Supco 120 solid state defrost timer with adjustable frequency and duration, I'd like some feedback on length of cycle vs frequency.

Right now it is set to 4 hours with 10 minutes of duration (= 60 minutes of defrost time per day) 6 hours at 15 minutes would be the same amount of defrost time, but I suspect it goes deeper than that. So which bias is more important, frequency or duration?. That likely runs deeper than that as well, hence the title philosophical discussion.

[abaesemann]

What came out of the fridge that this was put into?

Maybe a model number of fridge could help.

[Haywood]

I was hoping for a bit more general, but the fridge is a pre 1994 GE Monogram ZIS & the previous timer was an 8 hour X 15 minute motor driven one, the stock one is 16 hr 35 min IIRC.

[abaesemann]

Why I ask is that is where I would start with settings, Now if there was issues with those settings then adjusting accordingly based on your problems you may be having. So if there was not enough time for water to drain and it was freezing then keep duration and then change length.

[Haywood]

I installed the factory bandaid kit,GE WR49X10021 and while it improved defrost drastically, I could tell the glacier was gaining on me. the new timer is no doubt also a bandaid, but this time it seems I'm winning. I planed to experiment with it a bit, and settle on the least frequent, shortest duration that will get the job done & was curious what the thinking was as to the most efficient use of the available settings.

[Hiroshi]

8-10 hour frequency with 20-25 minutes of defrost time is the norm with mechanical defrost timers... Adaptive defrost software in newer models uses door openings as an input in when they "decide" to run a defrost cycle + cumulative compressor run-time, but they still usually have a 20-25 minute duration.

 

[Haywood]

Thank you, That's the sort of thing I was curious about. I'll set it for that (8-25) next time I climb up there, and maybe just leave it there. That is unless the glacier starts to form again. The adaptive route seems a logical evolution, I can see how they came to that. It almost aught to include a weather station, as I've noticed a sudden weather change would throw mine into a freeze up. That was before the improvements, early days, but hopefully it will be forgettable.

[Hiroshi]

Humidity is definitely a factor- the door opening statistics it gathers are, essentially, to address the humid air that fills the compartment whenever you open the door, and the fact if you open the door more often, you let more moisture in and it has to be eliminated through the defrost drain. The duration is so important because if the drain is frozen over by the cooling cycle kicking back in before the pan and tube is completely drained, it results in a "glacier." Every single model of refrigerator or freezer ( or AC for that matter) has to deal with this eventuality in one way or another...