Not particularly impressed with our (GE) fridge. Seems to be “running all the time”, and often not to be cold enough. To quantify this, I wired some 18B20 digital thermocouples to a beaglebone and let it go overnight. You can tell from the graph which is in the fridge compartment and which is in the freezer.

The data is from leaving the fridge alone all night. The small negative spike in the fridge data looks spurious. The first positive spike was opening the door for maybe ten seconds. The second positive spike was opening the door for maybe a minute. The larger temperature swings after it recovered from the door opening than during the night was because the thermocouple was accidentally touching an item of food overnight, and I moved it into free air when I opened the door.

The temperature swings in the freezer compartment are excessive. About 7°C every cooling cycle without opening the door at all; no wonder we get freezer burn.

I added a few more 18B20s and taped them all in place and set it up to run for a while. Sadly, the BBB is having trouble talking to two of the three thermocouples in the freezer, but it’s getting data from all three in the fridge. I don’t know if I’m drawing too much current or have bad connections, but I’m planning to just keep collecting data for a while.

At any rate, I now have EttF (Ethernet to the Fridge), so I guess that counts as Internet of Things. Yay? If this data leads us to replace our fridge, it’s unlikely to be a so-called “smart” fridge, though. One of my goals in life is to remain smarter than my home appliances.


Darren Hart June 13, 2015 17:02

Forgive me for asking the obvious - have you cleaned the coils recently?

Michael K Johnson June 13, 2015 17:12

The coils are inaccessible and theoretically are not supposed to need cleaning. I cleaned out the intake grill for them, though.

(“Not particularly impressed” includes many fit and finish items: drawers breaking, glides with an auto-disassemble feature that sends ball bearings bouncing around the kitchen, chilled water feature that works on alternate months, the list goes on but I’ll stop.)

I just caught the freezer going above freezing temporarily. I’m wondering if it’s a defrost cycle, and how often they happen. (The fridge temperature was not affected.) Now I’ll have data to find out…

Darren Hart June 13, 2015 17:15

You now have more empirical data on this unit than GE (or whoever manufactures it for them) ;-) 

Michael K Johnson June 13, 2015 17:29

One of the surprises is that one fridge sensor is consistently reporting 15°C (59°F). That makes me want to double-check with a “real thermometer”.

Behan Webster June 13, 2015 18:51

You know the grill comes off and you can fit a vacuum wand in the bottom of most fridges right? At least every fridge I’ve owned has worked that way. You can also remove the small compressor cover on the back which allows you to vacuum or blue out the compartment with compressed air. Makes a huge difference.

Who here actually believes the “no user maintainable parts” stickers on anything they own? ;)

Michael K Johnson June 13, 2015 19:10

Heated air blows out the grill. I haven’t figured out how to remove it yet, and it has electrical and plumbing embrangled in it, so I’m not eager to Just Pull Harder.

Clearly I’m not in the group that believes in such stickers, since I fixed the dishwasher that the repair dude said was unrepairable ($15 wear part) and the vacuum cleaner that the shop said was unrepairable (disassembled and removed the trapped junk). And so forth.

Converting the dying lawn mower to battery power instead of a new head gasket was probably overkill, but I’m much happier not smelling gas fumes! ☺

No, for the fridge, it’s more that I hate all its little brokennesses and am looking for data that backs up my inclination to try the grass on the other side of the fence.

Michael K Johnson June 13, 2015 19:19

My bad sensor problems are probably bad connections. I just fiddled with one of the sensors in the freezer and it started reporting data. Probably a dodgy mechanical connection. I just fed the 18B20s into female header strip and taped them in place, because I really wasn’t sure what topology I would want in the end. The final missing sensor is between the two working sensors in the freezer so it doesn’t matter very much.

Behan Webster June 13, 2015 19:20

You will find it is held on by spring clips. It will in fact likely come off if you pull harder. The first time it is removed is in fact the hardest.

Michael K Johnson June 13, 2015 19:34

Nope! Screwed in place. It would likely have come off if I pulled harder, but then it wouldn’t have gone back on very easily.

Other than dust around the plumbing and electrical, it was actually not that dirty.

Michael K Johnson June 13, 2015 19:49

Most of the noise is the variable speed fan that blows freezer air into the fridge and changes speed on about a 5 second cycle that is really annoying. Rumor is that it’s a common manufacturing defect and that GE will sell you a new mainboard for a ridiculous sum of money because you didn’t realize that you could get it repaired while it was still under warranty.

Cristian Gafton June 14, 2015 00:58

Three houses I owned over the years, in three houses I kicked out the GE/KitchenAid/Maytag junk to the curb and replaced it with Samsung fridges.

Eugene Crosser June 14, 2015 01:51

There are two ways to stay smarter than your appliances. One of them is is to keep appliances dumb… ;)

Behan Webster June 14, 2015 02:07

All my appliances are LG (came with the place). They’re pretty nice. The only weird thing is that they all play what is apparently Korean folk songs as their alarms (oven, fridge, washer, dryer). Only the dishwasher isn’t LG and it beeps incessantly when it completes its cycle.

+Michael K Johnson weird it’s screwed on. I’ve never seen one like that before. Though I would actually prefer screws to clips.

Michael K Johnson June 14, 2015 06:42

+Eugene Crosser sometimes I despair of the other way. ;)

LG and Samsung are the leading contenders. It’s only a two-foot-deep pocket despite the fact that it’s not installed along countertop, and if it sticks out too far the pantry door won’t open, so I’m limited to the very few countertop-depth options. :(

Michael K Johnson June 14, 2015 07:52

Cooling cycle last night was around 40-50 minutes off, one hour running; yesterday with the doors rarely opened (installing and testing sensors and removing food to eat; no food prep with frequent door opening and no warm items added), it spent most of the afternoon running. Only 20 minutes off between 3:30PM and 10:20PM.

I think I need to disassemble the back and see if I can get to coils to clean. That’s more likely than being low on refrigerant.

[Edited: I had previously reversed times for running and off]

Michael K Johnson June 14, 2015 08:18

Coil is in a cylindrical arrangement with only half accessible to be vacuumed. I vacuumed the accessible half; need to get a coil brush to clean the inaccessible half. Will be interesting to compare data from just vacuuming half of the coil to data after using a brush on the whole coil.

Darren Hart June 14, 2015 10:06

Were they particularly dirty? (nm, saw the photos)

Darren Hart June 14, 2015 10:12

Interesting that Samsung is mentioned over ge/Maytag/kitchenaid. My experience has been the latter are preferred from a serviceability and availability of parts, while Samsung (and LG) lack that, making then more or less disposable. Korean manufacturing appears to be advancing though. Sadly, all seem to be headed toward disposable.

Darren Hart June 14, 2015 10:13

There is always subzero/thermador/Viking :-) you know, if you have cash to burn…

Kim Johnson June 14, 2015 10:38

Looking at the GE website, it mentions that the compressor runs more on modern fridges than on older ones in order to save energy starting and stopping the motor. It does say that in warm or humid areas it will run close to 100 percent. Fwiw.

Michael K Johnson June 14, 2015 11:53

Only LG and Samsung have linear compressors. I’ve been massively disappointed by GE and Kitchenaid so far, so willing to try something different. +Cristian Gafton​ advised me to get a Panasonic microwave a few years ago and despite the terrible user interface it does a far better job of cooking the food than the GE it replaced.

Eugene Crosser June 14, 2015 14:33

In my country, LG and Samsung dominate the mid-low end. GE, Bosch and Siemens used to serve the hi end (mind you, European GE is different), now it’s Miele.

Michael K Johnson June 14, 2015 14:52

Cleaning one half of the coil with just a vacuum, no brush, cut the cooling cycle from an hour to 50 minutes. It also changed the fridge cooling cycle. I just now cleaned as much as I could reach with a brush, and I’ll see how much more of a difference that makes.

Michael K Johnson June 15, 2015 17:41

Hmm. I think that the 50-minute cooling cycle was a fluke. More data shows more 1-hour cooling cycles. Clearly need a few more days’ worth of data.

Michael K Johnson June 16, 2015 05:59

Caught another defrost cycle around midnight last night. For this one, it seems to have run the compressor for about 7.5 hours continuously, bringing the freezer compartment below -25°C for a few minutes before rapidly bringing it up to 0°C and then cooling it down. That reduced the total cycle time afterwards to a bit over an hour. This reduction in cycle time didn’t happen the first time I caught a defrost cycle, but it didn’t seem to do this “deep freeze” preparation for the first defrost cycle, either.

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