AquaPro Pro1300. Below 50 degrees the unit is supposed to switch into defrost mode, and shut down the compressor while running the fan to help clear frost from the coil. It is supposed to display "FS" on the display.

What actually happens is it displays F2, F3, F4, or flashes F5 and shuts off all together. I'm guessing that there is a configuration issue (this board is also set up to allow cooling operation, but the heat pump has no reversing valve).

I realize that there isn't much heat moving below 50 degrees, but it does help maintain.

Any ideas, or inside info on setting up the board on this thing?