We are installing a standby generator that has a feature to shed the load of the AC unit when demand is too high. There's a single contact in the transfer switch which they intend to have you use to break the Y wire to the compressor. We've got a single-stage Trane heat pump. Reviewing the thermostat manual and some online information, it looks like there's still just a Y wire to run the compressor and an O/B wire to switch the reversing valve. I'm assuming I can still just break the Y wire?
Related, what happens when the thermostat (Honeywall VisionPro IAQ if it matters) calls for heat using by turning on the heat pump but doesn't get any? Will it fail over to aux heat (i.e. nat. gas furnace here) automatically? I see some settings in the manual related to "droop control" which I assume are for this purpose. Here I'm not really concerned with comfort but with making sure the house doesn't freeze if we are away. If we are home, everyone in the house will be trained on how to put the thermostat in emergency heat mode if we are running on the generator.