I will need to know the model number of the heat pump and the manufacturer and part number of the new board to tell you the connections. Also, where the defrost sensor is located on the outdoor unit if you know.
I have a 1988 ruud two ton heat pump that will not defrost properly it has a new defrost board installed and a defrost t stat in high humidity conditions it will freeze up , it doesent shift into defrost but does changeover from heat to ac I do not know if the out door circuit board is wired properly it uses an external relay for the reversing vavle
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