Im working on a Frasier-johnston 4 ton heatpump ,8 yrs old.It was not defrosting and totally frozen over when I got the call.Jumping the board to initiate defrost done nothing so I orderd the board .The next day when I went back to install new board it was 52 dgrees outside and coil was completely thawed . I replaced board and coil temp sensor .It came on and ran and after about10 minutes I tried to jump sensor pins again to test defrost cycle. The fan slowed down and and the board started a clicking sound but never went fully into defrost . My question is shouldnt it go into a full defrost cycle when I try to test it or would the warmer temp outside not let the coil sensor call for it. And what else could keep it from test cycleing?