daytrader152:
liudr:
This is the LAST time I am asking you: what happens if you just switch the relays without solenoids connected to the relays.I would like to give you a definitive answer, but I can't. It took entire day to reproduce this problem once (with the solenoid connected). A few days ago I did disconnect the solenoid, and the problem did not occur for the entire day. However, it does not mean the problem would not occur without the solenoid connected. Until I find a consistent way of producing the problem, there is just no way to be sure.
En, understand. Try the capacitor then, just leave your system for a day or so and check back on the LCD. You don't need 10 uF something less than that will also work.