Mystery AC Device! Help?

Over the weekend I had 3 new devices detected. One of which has an auto-name of “AC” - but, it’s not my ac, as that has already been detected and works well (mostly.)

I’m at a loss to figure out what this one is. It’s drawing a little less power than my dehumidifier. I’ve just walked all around my house this morning trying to figure out what this is, and I’m just at a loss. Can’t figure it out. So I turn to you, Sense message board. You are my only hope!

Screen shots from the app showing this mystery device.

NOTE: Mystery device is “AC” - My actual ac is “Air Conditioner”.

It could be the fan blower motor on your HVAC system. If both devices tend to be on around the same time, this could be it. On my system, the fan shows up separately from the other components. I’ll see both components come on within seconds of each other, and once the thermostat reaches its set point, the non-fan components shut off (and disappear) while the fan component continues to run for another minute or so.

Since I (currently) have a gas-fired furnace, the fan component (shared between AC and furnace) shows up as “Furnace” which makes for some strange bubble configurations (seeing AC and Furnace on at the same time), but I know what it means, so I’m cool with it.

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My guess is that’s your air handler.

But if it was that fan wouldn’t it be on the exact same time as my AC? I guess I should compare the wave-graphs. Even if it is the fan, is the 331 wattage pull about right?

I was also wondering if it is the condenser pump?

That would be a huge amount for a condensate pump. And, no, such systems often run different components at different times. My heat pump and mini-duct have 5 different component5s, with different run times and powers. Making it more difficult, the mini-duct blower is variable flow (and power), depending on various sensors, and it ramps up and down…making it impossible for sense to detect on and off.

When they invested the architecture for Sense, they clearly didn’t understand how huge numbers of modern devices actually operate. LOTS of things aren’t a simple on and off, or just one power signature.

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That’s my concern. 331 wattage is pretty big for something I can’t quite track down. Maybe I’ll eat lunch down in my basement near my furnace and wait around see if these things correspond!

I like my sense, don’t get me wrong, but it seems more like a hobby device as opposed to something that is 100% working well. I sometimes feel like we are all just beta-testing this thing.

I think my HVAC fan motor is around 500W.

So, if I turn off the AC breaker - it seems to turn off that “AC” bubble. But the bubble doesn’t seem to correspond with the fan in my furnace at all. Besides the fan and a condenser pump are there any other elements to a central AC I am not considering?

Also related, my main Air Conditioning - which is detected also sometimes switches to “Other” when it is on…

And of course, I also have a detected “Heat 1” that is around 445 watts that I have no clue what it is either.

I have two simple central AC systems in my house that use the furnace air handlers / blowers for each floor to distribute the cool air. I have the furnaces on HS110s so I get to see exactly what’s going on with them. It’s cooling season right now, and my furnace blowers do come on independently from the AC compressor, though they are always on when the corresponding compressor is working. Just had a run this AM where the downstairs furnace blower came on without the downstairs compressor. It’s a little confusing because Sense just “discovered” the downstairs furnace blower as Heat 2, despite it already being on a smart plug.

Here’s what the furnace looks like on the HS110. 1400W spikes on AC turn-on, 600W usage during AC cycle, with only 400W during air redistribution cycles (blower with no AC).

@gjhead, what kind of AC do you have ? If your You have central AC that uses your furnace blower to distribute the AC cooling throughout the house, then your furnace and thermostat is on a different breaker than your AC. And your blower could show up as heat, like mine did.

There is one other element to the AC. The fan in the outside unit, the outside unit has the compressor motor and a fan.
For reference the air handler fan at my house uses 499 watt. I have two and they are close o the same.

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related to your mini-split - how did you start (or have you started) seeing them show up in Sense?
We have had a Mitsubishi for over a year and I have no idea if any of the random devices that are “detected” are related to it or not. Two inside air-handlers with fans and drain pumps, external compressor unit - all on one double breaker.

So an interesting update to this one. Last week, we had some folks doing some landscaping work in our backyard - which resulted in us having mov our outside AC unit and turn off our AC for two days. The entire hvac system was shut down for two days. And yet… that mystery “AC” device was still turning on and off!

I can only guess - but I really think there is some relation between the mystery AC and my dehumidifier that is on a smart plug.

The dehumidifier is on a Sense-linked smart plug? In that case you should be able to line up the signatures to a certain extent. How do “AC” and the dehumidifier compare?

Pulled the dehumidifier off of the Wemo plug - and now just have it plugged in directly. Seems to be matching up now. This really seems like Sense somehow matched a part of the pattern of the plug and detected it as a new device. Which ended up with both detections acting a bit wonky. I’ll keep an eye on this one over the next week and report back with more info.