I am trying to restore an inground system operating 3 zones. Here are the issues.

The system is installed at a residence which has been "shuttered" for about a year.

The automatic timer blows its fuse after about 15 minutes. Believe me, I give it no cause to do so.

As soon as I (manually) turn on the (reclaimed) water at the meter, all the zones go on. The fact that this main valve was turned off makes me believe that this problem might be a long-time pre-existing condition.

At the inground manifold, there are FOUR valves. One valve is different from the other three in that I could not locate a bleed screw on it.

I have concluded that this valve controls the supply flow. Is this a possibility? Why did they not install a simple ball valve to perform this function?

My fear is that one (or more) of the valves is bad; because I do not want to mess with valve repair/replacement.

Any helpful suggestions are welcome with my grateful thanks.