Hello, its most likely adjustable. If your thermostat has the outside air sensor option installed, it can be adjusted at the thermostat, other systems are adjustable at the outside unit.
30F was a good heat pump cut out temperature for older systems that used R22 refrigerant, usually 8 or 10 years old by now... newer systems that use R410a should be set between 15 and 20F to cut out and go into auxiliary heat mode.
There is a sticker on the outside unit that says what refrigerant is installed.
Take close up, exceedingly well focused photo's of the wiring diagram glued inside the furnace/air handler door, and the printed circuit board mounted on the blower, , that shows where the thermostat wires connect, and the thermostat wire connections, after you gently pry the thermostat from its wall mounted sub base... with the thermostat removed you can see the brand and model number of the thermostat on the back side of it.
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