Fixing the drip irrigation - again!

Note to self - what to do and what not to do when it comes to fixing the drip irrigation system. As often happens, the first time restarting the drip irrigation system (any 'system') something doesn't work. This time it was the pump cycling on and off. I figured that there had to be a leak somewhere. I checked all the zones and didn't see any leaks.

I manually shut off all zones and the pump continued to cycle. So I thought there must be a leak in the manifold section that distributes water to the zone valves. Here's where I was wrong - thinking that it must be something that I put together.

Digging out the manifold (next time I think I should put everything one the surface although I noticed that no one else does) there was a lot of water/mud. However, it was coming from the backflow preventer on the city water control valve. What happened is that the check valve failed and water from the pump/water tank was leaking through and overflowing at the backflow preventer.

I replaced the valve and tried again but the pump continued to cycle. I noticed a drip coming from the zone 4 valve which was manually closed. I pulled off the distribution hose and water was seeping through the closed valve. So I replace this as well and eventually got things up and running.

Lesson learned - don't assume that the problem lies with the part that was manually assembled. As unlikely as it seemed both problems were mechanical equipment failure.