How old are the valves and solenoids?
If you throw a new 24V controller on an old 12V system you are burnin the solenoids. Common short is likely. I have seen a situation on a golf course where the last valve on the run was sending back a surge because of distance and smoking the next solenoid towards the clock. Old rainbird EFV brass valves and the mainline was transite. Palmbrook CC. OOOOOFF