Failing air conditioner?

[RobbieG]

I have been getting some crazy high power spikes that I think are due to my air conditioner failing. I noticed it getting hotter in the house today, despite the thermostat saying the AC was running. Then finally it started to cool down. Looking at the sense power meter history, this time period seems to coincide with huge energy spikes every 5ish minutes or so, and then they stop once the overall energy usage increases. I’m assuming this is due to something like the compressor trying to start, and then finally starting? Any other thoughts? Or could this be normal? Screenshot attached.

[kevin1]

Try turning on the new Sense Labs option announced here:

About Sense Labs

Sense Labs is a space where users can try out our latest projects, share information and offer feedback directly to the engineers who developed them. Our first project focuses on electrical fault detection. We started with a motor stall detector, and followed up with a project related to power quality (including voltage data). We don’t expect to detect faults in your home perfectly, but we want to share our data with you as we develop our thinking around these projects. Your feedback will be v…

The Sense Labs area, once you enable it in Settings, includes an experimental “motor stall” detector. If you are having a typical AC compressor failure, it will likely show up as a motor stall.

Motor Stall - 3Ton HVAC

Below is an example of an unsolved motor stall:

[RobbieG]

Thanks, I enabled Sense Labs (the article was a bit confusing, it said " Sense Labs will initially be available in the web app is now available on iOS and Android". I enabled it in the android app, but nothing happened, so I logged into the webapp, enabled it there and it worked). It does look like it is classifying it as a motor stall. From what I’m reading in the links you shared, it could just be bad starting capacitors? Or does it potentially mean the motor itself is bad?

[kevin1]

Congrats on diagnosing !
Good blog on motor stalls below. Most common cause of AC compressor stalls is a failing run capacitor.

Identifying Potential Motor Stalls in Home Appliances - Sense Blog

Once you get is sorted out, you should post the waveforms and resolution here:

Sense Labs

Or at least respond to the survey here:

Sense Feedback: Motor Stalls

[pswired]

100% looks like a bad capacitor, cheap and easy fix. Nice work using Sense to confirm the problem.

[RobbieG]

Umm… I’m assuming the AC capacitor is not typically insulated, including rodent skeletons in the “insulation.”

No motor stalls that I noticed today, but I have ordered a new capacitor and will replace it tomorrow.

[waterboysh]

@RobbieG

I enabled it in the android app, but nothing happened, so I logged into the webapp, enabled it there and it worked)

I haven’t been experiencing anything like a motor stall, but I had turned Sense Labs on in the Android App, and like you mention when I checked on the web it was still disabled, so I enabled there as well. Not sure if that actually changes anything my Sense is doing or not though or if it’s just a UI thing.

[JustinAtSense]

@RobbieG @waterboysh Thanks for making us aware of this bug! We’re able to reproduce on our end and looking into a fix.

[kevin1]

Good luck with the replacement… Mind the exposed terminals that probably offed your little visitor. I think most videos on run start capacitor replacement include the step of shorting the exposed terminals together with a screwdriver after you have switched off the breaker/shutoff. Typically, a bad run start cap will have some external bulging, a physical manifestation of it’s failure.

[ixu]

That tableau gives a whole new meaning to Sense Labs.