The air conditioner works fine. When put in to the heat mode the out door unit trips outs on high head pressure but the indoor fan still blows. Why?

The air conditioner works fine. When put in to the heat mode the out door unit trips outs on high head pressure but the indoor fan still blows. Why?

Incorrect charge of refrigerant
Incorrect expansion device
Lack of enough heat removal by the indoor unit coil.
Defective or out of range head pressure control.
Partial restriction at change over valve.
Restricted drier
Noncondensibles in system.


Check all the above and post back.