Question
I have an ESP-8 whose fuse blows when the system attempts to start. The pump runs fine if I manually operate the main valve (RainBird 100-DV) . I have isolated the problem to occurring when only the main valve is connected. How do I check the valve to make sure it is the problem?

Answer
Mark,

If the fuse blows only when the valve is connected, it is either the valve or the wiring to the valve. You can test the solenoid with an "OHM" meter. The resistance should be between 25 and 50 ohms. If you don't have and ohmmeter, then try unhooking the wire from the valve at the valve. If you don't blow the fuse again, then for sure the solenoid is bad.

Matt