Hi guys, question where should I start looking, one of my valves will switch to spa mode from pool but when I go back to pool mode or shut off spa mode the valve will not return to pool.
Your valve cam could be set to where the valve is not to close after spa is shut down to allow water to flow through the spa when pool filter is running or you could have an issue with the motherboard of your automation system that will not activate the circuit to send the valve back to pool, you can always test this by swapping your valves from the back of the board from intake / return.
If your valve worked before then stopped I would change the microswitches inside the valve. They are easy to change and cost only a few dollars at digikey or other online electronics parts vendors. The part number you want is Omron SS-5T. The mictoswitches stop the rotation in each of the two directions the valve can turn. Usually, one of the switches will stick and not permit the valve to rotate in the opposite direction.