I have a york heat pump and a honeywell model 8300 thermostat. I also have a electric furnace as a backup aux heat. I have the thermostat set to go to 70 at 11:30 pm then at 9:30 am to go to 72.
then heat will operate in this mater.

1 At 9:30 heat pump will start
2 About 1 min later the aux heat will kick in
3. About 2 min later the aux will turn off leaving the heat pump running.
4. The heat pump will run for some undetermined time then turn off.
5. The temp in house will not get to the set point.
6. The blower will still be running. This will run for hours and the heat pump or the electric elements will not turn on. I disconnected the blower wire from the thermostat and the blower will still run.
7. i could the units working right if i change the thermostat to em heat for about a minute then wait for blower to turn off. i can now turn the thermostat back to auto and the heat pump run ok
I have tried the recovery mode on the thermostat it didn't help

labman

It sounds like you may have several problems on the control board. I am afraid the only answer may be a new control board.