The CB controls the Refrigerant reversing valve too.
We are having terminology issues in this thread. Note: Engineering terms to proceed.
Sea Water side...
1) 120 VAC water pump which is activated by CB. On and Off.
2) Outlet water flow should be
visible flowing overboard, if pumping. Verify this please HEAT or COOL.
3) Water Flow direction does not change. There is no internal water circulation.
4) There is a heat exchange between Sea Water and Refrigerant.
AC Refrigerant side...
1) 120 VAC Refrigerant Compressor [RC]. Starts and Stops by thermostat control panel.
2) Dual mode or HEAT or COOL
3) Thermostat Control panel setting decides HEAT or COOL Cycle.
4) The RC compresses Refrigerant in one flow direction.
5) There is a Solenoid Control valve that Reverses Refrigerant Flow in the Heat Exchanger only. No Water flow direction change.
Once you separate these issues. The Calvary will arrive.
Jim...