AOSmith Voltex model# PHPT 60 100, about 10 years old. Was working perfectly fine in "Efficiency mode" (ie, heat pump only). Turned it on to vacation mode today as I'm about to leave on a long trip, but now it won't turn back on to a regular heating mode. Whenever I press one of the 3 buttons to turn it back on ("Efficiency", "hybrid", "electric"), nothing happens. I am, however, able to to press the °F/°C button and the Lock button and turn it off with it's power button.

I've also tried shutting it off and back on via breaker, but no luck.

How can I get it working? I'll add I'm fairly handy with a multimeter and soldering iron if needed.

EDIT: Whenever I press the "efficiency", "hybrid", or "electric" buttons, the backlight turns on, so that indicates it's at least recognizing the button presses.

1 Answer 1


Figured it out, it was a combination of user error and a misleading user interface.

I had to tap the vacation mode button again to toggle off vacation mode. Half the time it would default back to efficiency mode, some other times it would default to "electric" mode.

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