Mystery Device: 700W for 2-3 seconds every 30 seconds

Those spikes usually indicate a motor, especially at the beginning of the waveform. I do have a heating element that also has spikes so it can be confusing.
What you have appears that it could be a motor or heating element to me. That’s a lot of electricity at 700 watts.
The only device I have that comes on every minute for a few seconds is a Keurig, I wonder if you have something malfunctioning?

I see it’s getting warm-ish in Virginia … this is probably a dumb question but is your AC on?
Seasonal transitions are notorious for AC-on-while-heating-is-running type issues.
You have a different heating and cooling systems so … just asking.

Do you have a well or other water pump?

I don’t have a water pump, as I’m on a municipal supply. I’m leaning toward something malfunctioning because, as I said in the original post, my wife and I were just watching TV when it started (unbeknownst to us at the time). If firgured my oldest son might have been awake, but I already checked everything in the kids’ rooms.

My heat pump is configured for AC only. It won’t run when the heat is on. I’ve double-checked that the heat is not on for either level (two thermostats, air handler has a damper to direct air between levels).

If you fridge is detected you can look to see the compressor consumption. If it’s running more than it should then the defrost could be stuck or malfunctioning. Those defrosters are usually around 500 watts or more

I just realized that my sump pump hasn’t been recorded for 5 days. I wonder if it started malfunctioning. It’s around 700 watts.
Supposed to rain this weekend, so I guess I’d better check it out tonight.
This is what is normally looks like:

It hasn’t been recognized yet, but you gave me a thought. Maybe it’s the defrost cycle. I don’t know how long that should last…

Edit: wow, my skimming your post was really bad. I guess my brain saw defrost even though I was thinking you meant compressor the whole time.

My defrost lasts 11-15 minutes once to twice a day

I would guess if the defroster is running on that cycle, even though it’s a short spike, it would seem enough to make the fridge malfunction. Perhaps.

Stuck sump pump sounds like a probable target … that’s what I intended to imply when I suggested “water pump”

Could be the float on a sump bouncing up and down. Probably nothing wrong with the pump itself but the float mechanism like a sticking toilet

Given the frequency of the cycles, you’re probably best off doing a “binary search” by turning half your circuit breakers off, waiting to see if the device continues, etc.

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It was the laser printer! Seems like my wife printed some things, but it ran out of paper. I guess it was just keeping warm until someone added paper.

Thanks for all the help!

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Wow, I don’t have a laser printer but I’m really surprised how much electricity they use. If it uses 700 watts for “keeping warm”, how much does it use when it’s actually printing?

For the most part they don’t. I think the key part here is that the printer was in the middle of a print job and waiting for more paper to finish, so it may not have gone back to an idle state.

My laser will “keep warm” for about 5- 10 minutes after a completed print job, and then go back to a proper idle state. Some printers you can define that a bit more. Often in a setting called “fast start” or something like that where it keeps the fuser warm so that when you send a print job, it can get that first page out a lot faster.

Screenshot of my printers fuser (Sense Detected) below. If memory serves, I sent two jobs about a minute apart in the first chunk, and then a third page around 3:22. Not detected area all the other parts of the printer (rollers, paper feed, fans etc…)

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I have a Brother HL-L23600W

This was printing 3 pages and going right back to sleep:

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My laser printer (Brother HL-3170CDW) uses about 7 watts in “sleep mode”, so I don’t even bother to turn it off. While printing it runs about 500 watts (measured on my Kill-a-watt…Sense hasn’t found it). While on “standby”, between jobs and before it goes to sleep, it runs about 55 watts, keeping the fuser warm I’d guess.

700 seems really high if it was just sitting there, but behavior during a paper outage is certainly device dependent.

So, Sense found a hidden power drain problem for Phil, cool!

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Loving this thread.

How did I not think of the fascinating energy signature of a printer! Possibly because Sense hasn’t ID’d it and I print infrequently.

So, I just quickly migrated my printers onto a TP-link Kasa HS300 so I can look at the curves and am amazed at the peaks. Mine, a Brother HL-5470DW, actually spikes at what could even trip a 15A circuit and the 1875W HS300 but is brief enough to not cause problems.

First peaks are printer power-up and following 3 are single page prints.

I have a second Sense that I use for testing that I’m going to temporarily put on the printer alone and try and grab some more details.

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My kids already hear me complain about paper and ink, now electricity too?

I think we’ll be fine … just DON’T PRINT THOSE GRAPHS!

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I don’t see such detail on my Kill-a-Watt of course, and Sense just lumps the printers in “Other”. These are fascinating wave forms…who would have thought? Thanks.

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