I have an upright refrigerator I use as a fermentation chamber. Lately it's been not turning on to a cooling cycle, even though the temperature controller is telling it to do so. It doesn't happen all the time, and eventually it does turn on, probably after about 30 minutes. I have a johnson controls A419 temperature controller. When this happens, the green LED turns on, but the fridge doesn't. It isn't flashing ASD. The fridge doesn't feel hot, or like it has been continuously running. I don't think it's the compressor. I had a chest freezer with a bad compressor, and it would just never cool down to the set temperature. Once my fridge turns on, it gets to the set temperature without any issues. Like I said, it doesn't happen all the time, but it is beginning to worry me.