FHP model EMO048-3HZC serial DAO97215. Original call was continous blower fan, the cause was stat never would satisfy in heating mode. This is a water source heat pump. My loop temperature is 77 degrees F, clean strainer and 12 gpm flow. Charge was removed and weighed back in. Metering device is cap tube. 70 degree indoor temp, low load. Blower speed low. Cleaned evaporator and checked blower rotation. Cooling mode pressures 75/250, 0 superheat and 18 subcooling, 20 degree delta across evap. Heating mode pressures 36/175. Now here's the kicker 50 degrees superheat?? Reversing valve appears to be shifting properly. In heat mode refrigerant cap tubes frosting back to condenser loop? In order to bring heat on until I can resolve this problem I blocked about 2/3 of evaporator coil. Cap tubes are suspect but why the difference in superheat from heat to cool? Any help greatly appreciated.