Hi, I have a question regarding derived three-phase: Should I always pick the phase that gives the highest power reading? One example: Right now my heat pump reads 1300W on phase B, 880W on phase A and 440W on phase C. If I use phase A or C, I get reverse polarity symbol in IotaWatt’s status screen.
Now, it has been on phase B the past week or so. I have compared kW/d readings with the heat pump’s own reported daily power consumption (on the unit’s screen), and the Iotawatt consequently reads higher consumption than reported by the HP. Typical values are
Tu: 20 kWh vs 14 (HP disp), IotaWatt 43% higher
Wed: 25.4kWh vs 20 (HP disp), IotaWatt 27% higher
Thu: 13.2kWh vs 9.3 (HP disp), IotaWatt 42% higher
So the factor is not entirely constant, but sort of. AFAIK, there are no other users on that connection. If the IotaWatt had been set to phase A, it would have given slighly lower (but closer) readings than the HP, while phase C would obviously be wrong.
What is the correct setup? Is my heat pump under-reporting??