Please, note that in electronic you have always to supply the clean with the dirty !

I mean that the power devices which may disturb by conducted emissions as your valve or relays should be supplied first. The sensibles parts may be supplied next. Thus, the conducted interferences will loop in the power supply and the sensibles part will be safe.

Note also that you may design two separate power supplies. This can be achieved by using a diod and a capacitor just after you diod bridge to supply your valve. Your remaining electronic should be supplied in parallel with a regulator from the same diod bridge.

I will add a part on this in my website 'design rules' chapter.


regards
Stephane