2 Master Valve and up to 2 zone Operation wiring for Less than $20 Tested no more Master valve zone Fault

Okay. I see.

That is why I suggested sperate common especially when multiple equipment introduced in an overall system. It may get complicated.

If you just separate out common for 24vac terminal, it may work. But again, I don’t know your entire system, and given you have long runs or cables, it may be tricky to resolve.

Good luck. I am glad atleast solution I put out worked as intended for you.