Phase issues with known 240v devices


#1

So lately I’ve been experiencing a bit of chaos with known or partially known sense devices that are on 240v circuits. Specific devices are:
Water Heater
Pool Pump
Upstairs Heat Pump/AC
Downstairs Heat Pump/AC

My water heater and pool pump have been pretty accurate for a while even though the pool pump initially was detected at half its power draw then after about a week, the 2nd half joined it.

My downstairs heat pump/AC is a new device but seems to be grabbing both sides of the 240v.

My upstairs heat pump/AC is also newly discovered but so far sense has only picked up half of its power draw. I’m hoping the 2nd half will soon join it like what I experienced with my pool pump in the 1st week of its discovery.

So that’s where I stand on these devices but over the weekend and maybe even end of last week, here’s what has randomly occurred…

240v devices like my water heater, pool pump, and downstairs heat pump/AC have randomly started kicking on with only half of their power in the appropriate red bubble and the other half in other. At times, I can see this happen and turn that device off, then back on and it then grabs all of it, or maybe not. It’s random. Other times it may kick on correctly only to lose half of it while running.

The chaos this has caused is twofold:

  1. my historical usage data is invalid
  2. I’ve seen things like my AC running at the same time as my pool pump. The pool pump then loses half its known power. The AC turns off in real life, but sense gives the now lost pool pump power to my AC that turned off and thinks both are running when the AC isn’t.

The frustration is this sort of behavior seems to happen randomly and usually while I’m asleep or otherwise not home to argue via the “not on” with sense.

Has anyone else experienced this sort of behavior? I’m worried if I can trust sense to keep my 240v devices accurate since this seems to be happening after clean detection for a few weeks.


#2

From my experience, you can NOT trust Sense with 240v devices. I’ve had my Sense Solar since December of 2016, and it has never reliable tracked 240v devices.

The only thing it does reliably is track total daily usage. It agrees within 1 kWh daily of my usage with my utility company.

In my case, most every 240v device tracks only 1/.2 the usage, with the balance being “Unknown”

For evey one of my 240v devices, it tracks (1/2 usage) for a few months, then forgets and relearns as a new device. Impossible to track historical usage.

40% to 80% (depending on month) of my monthly usage has been “Unknown” since I first installed the unit.

Support always says “We’ll look into it”, Never happens (that I can tell).


#3

Well that’s not what I was hoping to hear. I’ve been trying to figure out if some of my electrically noisy devices like TV being on or NAS running heavy disk activity could be making one phase or the other noisey enough to mess up detection.


#4

Interesting. Sense has (so far) only picked up on one of our 240v devices, but we’re only about a week in. It found our well pump. The kitchen oven and the clothes dryer have yet to be detected and both have had a bit of use the past week. It is still too cold for our two AC condensers and two AC air handlers to turn on and they’re the only other 240v devices here.


#5

My Sense has detected 220v devices, including my geothermal heat pump, my hot water heater, and my dryer. In fact, it’s been much better with 240v devices than 110v devices, but I do have to say that it doesn’t monitor them reliably…sometimes a running device shows up in bubbles correctly, sometimes as other, sometimes not at all, even though Devices shows running (web app). I also have a Welserver, which monitors my higher power devices on/off individually…I bought Sense to measure power-use device by device individually….sure wish it did.


#6

My heat pump is detected pretty reliably, the water heater not so much. It’s been that way from the start, either missing it entirely, only getting half, or about half of the time getting the full draw. I’ve had several posts on it, contacted support several times too.

A fix ain’t coming, but I’m not worried. I can very plainly see when it’s running and how much energy it uses.


#7

…though it sound likes @bduthie 's experience would be (to use your heat pump as an example) 446w is from one leg and another roughly equal amount is used on the other leg yet reported under ‘other’.


#8

Oh, the 446 is off-center. It’s using about 5kw.


#9

Have any of you attempted to correlate other things going on around the house with the times mis-detection of the 240v appliances happens? Ideally I’d like to try to re-create it on demand then engage support.


#10

Anecdotally, that’s exactly the case. My water heater seems to be much less likely to be detected if either the television or heat pump is running concurrently. If the water heater comes on before the heat pump, then the heat pump gets a missed detection.

As far as only picking up one leg, I haven’t come up with a good explanation.