I personally think you should thank your lucky stars you can turn this "feature" off.
Can't on the ZEN04, which occasionally also has a mind of its own, but can't be turned off.
It's a peripheral result of being too smart for its own good.
If it was just a dumb switch, no problemo, right?
But you're using it to monitor power, I assume.
Presumably, since its new and does heat the water, there's a heat pump involved, like my fancy new washer/dryer combo. Perhaps that's a factor...in some way.
edit: I actually have used the ZEN15 to monitor power on my fancy COMBO.
edit2: It could still be a factor in your case.
