“no idea”. Load

I have a semi regular load event I have named “no idea” It comes on about every 24 hours, peaks at 100w, quickly levels off at 50w for anywhere from 1 hour to 4. I have ruled out computer UPS, freezer defrost. We don’t have any sump pumps. Stumped. Any ideas?


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It’s clear by your pictures that it’s a device with “starting watts”. That limits the range of devices that you have. Typical devices with starting watts:

  • Well Pump
  • Furnace/AC
  • Dishwasher
  • Washing Machine
  • Clothes Dryer (gas & electric)
  • Furnace/AC Fan Only
  • Some EV’s (mine doesn’t)
  • Quite a few power tools
  • Sump Pump
  • Water Heater
  • Refrigerator/Freezer
  • Window AC
  • Garage Door Opener

Since it’s really low on the power side I would think of things like maybe a bathroom exhaust fan, attic fan, subfloor exhaust fan, range hood or some sort of low powered motor. Maybe even a recirc pump?

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This is a great list from @DevOpsTodd - I definitely would 2nd the idea that this looks like a low-powered motor / some type of fan.

Does it come on the same time every day, or does it vary a bit?

Thanks for insight. Great info.

I will continue on the hunt… it’s only 50W, so it is more about the mystery and intrigue. I have my internet modem on a ups, so next time it comes on I can shut down every circuit, one at a time until I isolate.

It’s definitely something coming on automatically… it triggers nominally every 24 hours. Its not anything we use in our daily routine, because it also turns on while on vacation (so that rules out many things)
I don’t have any exhaust fans, or sumps. We do have spa, which has a circulating pump… but turning that off, doesn’t kill that load. I’ve also ruled out the refrigerator and freezer.

Just about every day. Nominally 7 pm. Stays on from 2-6 hours. I’m on the hunt and will post when I find it.

@jwpiersol unless your UPS is defective you should not have starting watts on it. Starting watts, the spike you see at the beginning, is the extra power needed to spin up the device. There’s nothing to spin up in a UPC.

Could you have something that triggers just your AC fan? For example many thermostats will turn on the fan when humidity gets too high.

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Note that turning off a circuit breaker will not necessarily cause the sense-detected device to be detected as off. The signature of the device switching off normally may be different than the signature of the breaker turning it off. Remember that Sense is using millions of samples per second to try to catch these transitions.

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Thanks for the tip … I was hoping to at least use breaker-off to at least isolate the circuit. My plan was to turn off breakers one at a time; waiting a min or so between each.

Correct, that would show in the power meter, but not necessarily in the device on/off. So it should help you figure out which breaker your mystery device is on.

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SOLVED. It was a small circulation pump that is part of a hot tub. Thanks to @andy - I realized that shutting off the breaker did not necessarily mean the device would drop off. So suspecting the hot tub - I shut it down for a few hours, then re-energized it. As soon as it was energized - the “no idea” load popped up. Hallelujah!!! Thank you.

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