Water heater should be easy to detect...but sense still doesn’t see it

Picture from this evening. The bumps are successfully detected as the well pump kicking on and off. How can sense not figure out the over 4000W item that came on with the well pump is the water heater .? This should be an easy one: there aren’t many things that can pull 4000w.

Patience. My water heater is detected correctly about 80% of the time now. I believe it has improved now that our heat pump is running less frequently, over the summer it had a detection rate of less than 50%. Part of the problem is that its a 240v circuit, partly because it’s rare to have it run any entire cycle without several other appliances coming on which may make it more difficult to detect initially. Looks like this morning it only picked up 120v:

I am being patient. I am just annoyed that sense isn’t finding things I think it should be able to figure out…

Sense should try and target the 220 appliances first. It found my garage door at < 500W, but it can’t find the 4000W water heater ?

Is your a dual element or single element water heater ? Most of the ones I’ve seen are dual element, and the top element doesn’t come on as often as the lower element. They have individual thermostats, and the top of the tank stays warmer than the bottom. So I would guess sense didn’t miss 1/2 the load of your water heater and that only 1 element was on. But that would just be my guess.

It’s a dual element, about 12yrs old. I agree that sometimes both elements aren’t meant to come on, but on the whole-data line graph and from the bubble data both are certainly coming on :slight_smile:

What I wonder is if there were some difference in the order they were coming on. Top then bottom - detects readily. Bottom then top - only gets half. On the other hand, there certainly were times over the summer when it was missed entirely, soooo…

In all the dual element water heaters I’ve seen, they are wired so only one element can be on at a time. So the fact that Sense is detecting only half the load is not because only one element is turning on.

Under normal conditions, the bottom element, usually the higher wattage element, is the one that does all the heating. Its the only one that turns on and off. However, when there is heavy usage, like during a long shower, where cold water is entering the heater and the lower element cant keep up, then the lower element is turned off and power is applied to the upper element. The upper element is located closer to the outlet of the water heater, and since hot water rises, it must keep a smaller volume of water hot and therefore keeps the water temperature warmer than what the lower element could.

Sense does the same thing with my water heater, detecting only half the load. I’ve always figured there is something on one of the power legs that is interfering and keeping Sense from detecting that leg. Be it noise, or a heavier load on the 240 legs is unknown. Nothing will improve until Sense’s learning algorithms improve to handle this situation.

I have seen situations where a heavy load keeps other loads from being detected. Whenever my microwave oven is running, the garbage disposal is not detected yet it is detected just fine if the microwave is off. The same thing could be happening with the water heater.

On my GE40M06AAG HWH both elements are wired in what appears to be parallel for a total of 4700 Watts. There is a slight (second or so) between the two elements coming on i.e. a step in power.
Came that way from the mfg.

You could try reversing the leads from the two splits in the phase feeding the sense unit. Perhaps having the “usually on” heating element feeding the other side would be more likely to be detected (not that it SHOULD be, just that it MIGHT).


I think it more appropriate to swap leads at the water heater - lord knows where swapping the leads for the sense unit would get you :wink:

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