When the power comes back on after a power cut, your air source heat pump controls will all come back on again normally, and there is nothing you have to reset.
If the power cut has lasted a long time (12 hours for example), it's much better for your system to start it back up gradually. You may start by just warming up your hot water cylinder. If you have thermostatic radiators valves (sometimes known as TRVs) turn all but one off, and as your radiator starts to warm up, turn another back on, and so on.
Please watch our video for a more detailed explanation.