Thanks for your thoughtful response… and sorry it took so long to get back to you. I tried different combinations of capacitors, a diode on the load lines, etc… nothing worked. And then I put a 0.1uF capacitor directly between the power leads on the valve itself… and everything started working fine. Admittedly, I’m not 100% sure why… but I won’t complain :)
Shift register > Relays - inconsistent results when load is attached to relay (discuss.tchncs.de)
First of all, I apologize for the lack of a “formal” schematic… I tried to draw one out, but got buried in the nuances of it :)...