[FrankJ]

You can only 8 solenoids to a solenoid break out. That is all you get at 24V. Your valves have 2 solenoids that is why you can only control 4 valves. Going to a single solenoid valve will allow eight valves assuming you stay in your power budget.

If you read R51 in its entirety & look at chart 4-4 above the reference about multiple loads you will see it only applies to spikes.