I have a heat pump / oil furnace combo for my house. The heat pump provides central air in the winter and then heat as long as the temperature outside is above a certain level. Then the oil furnace takes over. IT always swicthed for the heat pump to the oil furnace on its own usually at 38 degrees outside temp. But so far this year the oil furnace has been kicking on when the temp outisde is in the mid 40s. Any idea if this is an adjustable setting somewhere or if I need to have someone who knows what they are doing look at the system? Thanks

The setting should not have changed by itself so the system is probably having problems that a homeowner cannot repair. One thing you can do is make sure the thermostat is set correctly or as it was always set before the problem started.

You will have a thermostat in the outdoor unit that is adjustable, but these are field installed and may not be in the same location , might want it adjusted by a service tech, good luck, Mike