I currently use 10 position 3 stack rotary switch, only because that’s what dultmier sold me when I overhauled a closed wash I had purchased. Why 3 stack? Why 2 stack? Advantages or disadvantages of each?
No advantage or disadvantage, it's all about necessity. Are you using all three stacks now? Is there any position (other than 10, 20, and 30) that has a wire on all three screws?
Mep, could someone wire in relays instead of buying three stack switches? The price difference between two and three stacks seems significant enough to make me think about it.
I've done it with IDX pushbutton switches, they have one output that you program for high pressure functions but we needed another output that triggered off of two selections for a common air solenoid. I used the cheapest SPDT Omron relay, soldered the wires right to the terminals and attached it to the end of the terminal strip with a mounting ring cable tie.