Elusive Pump Operations

I have been unable to identify a “pump” that was detected several weeks ago.
The power meter for the past 24 hours shows it cycling on and off rapidly about 20 times (sorry but the system restricted me to only one image).

Here is the waveform:

I have determined this is not the sump pump, the condensate pump, the washing machine, or the (gas) hot water heater exhaust fan but I have been unable to figure it out. Notice that it runs only for a few seconds, so it is difficult to track it down after I receive the notification.

I will appreciate any ideas you may have on what this is or how I can better identify it.


Welcome @lee
How many watts does it use and how often does it run?
You said rapidly cycles but I can’t see the time, sorry.

It draws 123 watts.
It was on 19 times in 24 hours. The power meter for the past 24 is now shown below.

Appears to run more during the day. The short cycle times look to be just a few minutes, I wonder if could be ice maker motor on refrigerator.

Thanks for this suggestion.
To check it out I raised the ice-maker bale to turn it off around 3 pm yesterday.
Since then Sense reported several operations of the device, so it seems unlikely this is the ice-maker.

Coincidentally, at almost exactly the same time, Sense reported that it found a new device that it suggests naming “ice-maker”. I tentatively took that suggestion and allowed the ice-maker to resume operating. I’ll track the new device and continue to investigate the mystery “pump” device.

I have finally identified this as the condensate pump.
It is NXTGen model VCMX-20ULS.
With the arrival of summer the air conditioner runs regularly, this triggers the pump often, and I tracked it down.

The pump was first detected during the winter and I did not realize our natural gas fired heater has a condensate drain. I should have recognized that water is a product of natural gas combustion.
CH4 + 2O2 -> CO2 + 2H2O



Fascinating nuggets of gold!

Sense: We need a Sense-native clearinghouse for these revelations.

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@ixu, @lee,

If you are willing to post with prescribed screenshots, we can set you up to post in the Community Device Library:


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Here is the power meter over a few hours:

And here is one operation expanded:

These are for the NXTGen model VCMX-20ULS condensate pump.

I hope this is helpful.

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