Old Fridge Defroster Found After Two Years

Several weeks ago, I got a mystery device connected, and the list of community names wasn’t at all helpful. I knew it wasn’t my non-existent jacuzzi, not a 300w light. I know when my furnace kicks on, so not that either. I checked the energy usage of our old-school coffee maker, and it wasn’t that either. The frequency (once every 24-48 hours) and duration (10 minutes) made me think it was a defrosting element, but I couldn’t prove it.

Until today. We have an old fridge, from early 2003, with no features. None. Not even an ice maker. It is a fridge on top, freezer on bottom. I believe this was the first device Sense discovered, and did so just a couple days after powering on my Sense in Feb 2020. I was previously able to prove my kitchen fridge’s defroster by finding the part for sale and cross checking its power requirements with Sense’s power usage. While I was able to find the part from a 2003 fridge, there were no specifics for it.

Finally, today in the middle of the day, it turned on. I went to the circuit panel, killed the breaker I thought it was, and saw 433w drop. Hmmm, this mystery device was only 300w. I turned the breaker back on, and saw the answer. While this mystery device remained off, or undetected by Sense because of a change in pattern/on-off signature, Sense did see my fridge using 140w.

There we have it. 140w for the compressor, plus 300w for the defroster, equals 440w, or roughly the 433w that went away when I killed the breaker.

If I had one question: do defrosters and compressors regularly run at the same time? My modern fridge runs one of the other. Anyways, another mystery solved and a new native detection, albeit almost two years after the parent device was detected.

Generally no.
Some commercial units (like a walk in) do have a reversing valve, but that is unlikely for any consumer grade fridge.

I can’t speak in general, but my 2018 Samsung refrigerator seems to defrost at exactly the same time each day, so I suspect it’s sophisticated electronics control that. None of its other power draws (variable speed compressor, ice maker, lights, etc) run on a timed basis and the refrige as a whole wasn’t Sense detectable.