I recently switched over from installing one brand and am now installing Rheem units. Needed a new unit myself, so I installed one on my own home, so I could give an educated opinion of the unit. Everyone elses is operating correctly....BUT...mine isn't! When the unit goes into defrost (HP) it will initiate the cycle, and come out, but won't restart the unit in heat mode. There is a rapid "clicking" noise in the unit, which I believe is coming from the RV. The relay on the board is also simultaneously "clicking". I use emergency heat to satisfy the stat and on the next call for heat, the unit starts normaly and works fine....until defrost time!!!! Then the entire sequence is repeated.... Bad Board?