Once again, a little bit about the refrigerator: It's a refrigerator (only) that I've had for some years and it has given me trouble before; I even had to have the evaporator coil replaced. I got this thing because I wanted it to be the last refrigerator I'd ever buy. To meet that I got the very top of the line GE Monogram model ZIRS36 in stainless steel (ZIRS36NMRH). It's a really, really old design that doesn't even have a frost free option. That's because it has no freezer inside and just doesn't form frost.
Basically, the power comes in, goes to the temperature control, then to a temperature sensor on the evaporator coil (to prevent freezing up) and then to the compressor. There's three fans: one on the top to cool the condenser and condenser coil, one inside to circulate air from the evaporator coil to the rest of the fridge, and one on the bottom to evaporate any water that drains out of the evaporator. Then the lights are all that's left. Not much to go bad, and not much to troubleshoot when it has problems.
However, I couldn't find anything wrong with any of those things, so I went to the web and found this discussion on one of those 'Ask an Expert' sites <link>; basically, the expert said the correct thing first, then corrected himself to the wrong thing. This fridge is a middle level cooling system. It doesn't cool below freezing anywhere inside except the actual surface of the evaporator coil. It maintains a temperature of about 38 degrees and doesn't need a defrost timer or defrost heater at all. The customer in the discussion tells the expert this, but that doesn't keep the expert from getting confused and messing it up. I chuckled a little bit and then found this discussion <link>; once again, the expert changes his mind midstream and messes it up.
The last link is especially interesting because a couple of other repairmen get into it and try to straighten things out. By the very bottom of the discussion, the actual possible problems finally show up.
So, what was wrong with mine? The door needed to be adjusted. Yep, the door has sagged a little bit over the years and was far enough down that it didn't close a switch at the top that turns on the fan for the evaporator. See, if the fan isn't on, the evaporator goes into freezing range and the temperature sensor I mentioned above, shuts off the compressor to prevent ice forming and breaking the evaporator coil. I drug out the tools and modified the top hinge to be adjustable and reset the door. Problem solved.
The reason I had to modify the hinge was because GE made provisions for raising and lowering the door, but not tilting it. They even avoid the subject in their installation manual (yes, I read it) like a door will never, ever skew a little bit. The experts out there will tell me that I should adjust the fridge to assure that it's square because that can cause the same problem; I did that first with a nice level, framing square, and all. Nope, the door actually needed to be adjusted.
But the point of this is that after I found the two discussions listed above, I found several others where the expert just wouldn't listen to the customer, assumed he knew everything, and screwed it up.
I'll never, ever ask a question on one of those sites.
But, there were a few good things that came out of this fiasco. I moved the Smart Switch back to the fridge (I had it on the freezer for a few days), and took a look at the power usage during the problem:
Notice the small spikes? It seems the compressor was turning on for a very short period, then shutting off for a very long period. This was because the evaporator coil got too cold (no airflow) and the thermal protection kicked in and shut the compressor off. This is very different from the graph I blogged about earlier <link>. Another thing good about this was that I improved the performance of the appliance:
Now, the compressor is on longer, but off longer as well. I turned the temperature control down and allowed it to stabilize at 38 F and all seems to be well. Of course, something else can crop up and cause problems, but it looks like I fixed it.
Edit: It's been a little over a day since I fixed the door on the fridge and I thought someone out there might be interested in the result. Yes I fixed it, and I made out like a bandit on this: