When the set temperature has been achieved the thermostat turns off the furnace fan but the heat pump fan in the unit outside continues to run until after a couple of minutes it trips the reset switch. There is a loud hum coming from the furnace while this is happening. I flipped off the breaker for the heat pump yet when I flipped it back on after a couple of minutes the heat pump fan will come back on though the inside furnace and fan is still off. Any ideas?

When the set temperature has been achieved the thermostat turns off the furnace fan but the heat pump fan in the unit outside continues to run until after a couple of minutes it trips the reset switch. There is a loud hum coming from the furnace while this is happening. I flipped off the breaker for the heat pump yet when I flipped it back on after a couple of minutes the heat pump fan will come back on though the inside furnace and fan is still off. Any ideas?

Additional information for the above post. Even when I switch the thermostat to the off position the heat pump fan continues to run.

Sounds like your starter/contactor in the outside unit has the contacts welded together. This will cause the outside unit to run all the time or until it is cut out by the reset safety. It is best to just replace instead of burnishing the contacts.

Sounds like your starter/contactor in the outside unit has the contacts welded together. This will cause the outside unit to run all the time or until it is cut out by the reset safety. It is best to just replace instead of burnishing the contacts.

Thank you very much HVAC 1000.