DCM turned off

Earlier this week, the DCM that I use to monitor my heat pumps started reporting on/off repeatedly. Here is my DCM Power Meter for the past 2 nights. Tuesday night is what’s expected, Wednesday night is the on/off cycle. Heat pumps work fine both nights.

Here is a summary of the events in chronological order:

  1. Heat pumps idle at 20W, DCM Power Meter reads 20W
  2. Heat pumps ramp up greater than 22W (12:02 AM)
  • DCM Power Meter reads 0W
  • Sense Power Meter picks up Heat Pumps
  • Timeline reports Heat Pumps turned off
  1. Heat Pumps back to idle at 20W (12:08 AM)
  • DCM Power Meter reads 20W
  • Sense Power Meter normal
  • Timeline reports Heat Pumps turned on
  1. Cycle starts again as #2 above (12:27 AM) and repeats

Here are the Device Timeline, DCM Power Meter and Sense Power Meter from last night, starting at mid-night

Any insight is appreciated.

Hmm, if we were dealing with a smartplug instead of DCM, I would have posited data dropouts, which can happen for a variety of reasons. But three things make me think it is something else that I have never seen.

  • The DCM pattern on the right looks like a clipped and down-biased version of the pattern on the left.
  • The DCM drops to zero have falloff and return curved edges to them - not typical of data dropoffs
  • DCM seems more unlikely than smartplugs to have data dropoffs.

My guess is that something happened with either the DCM CTs, CT connections or CT configuration/calibration (that’s in software and can original back at the Sense mothership). I would contact support@sense.com.

ps: We’ve seen the configuration/calibration for working Sense solar installations get spontaneously corrupted recently. Guessing the same could happen for DCM.

Appreciate the reply. Been working with support for 2 days now, just got bumped to Level 2 support. Let’s see what happens.

Level 2 support found that the DCM detection was inverted. Instead of power meter going up, it went down reporting an off state. Don’t know what caused it but I am glad it’s working again.

Thanks for the update. Sounds like DCM is prone to the same “accidental/sporadic” reconfiguration issue that some solar users have seen, where a correctly configured, working set of second port CTs, gets corrupted.