How to Repair Indexing Valves (sprinkler systems)

[@joezada3681]

Hello Michael. I do have a 4-zone index valve with 3-zone Cam. Does the 4th unused zone also must be capped off? Reason I'm asking because I think when the Sprinkler water pump stops, the water momentum "un-primes" my water pump.. After I prime it and it works fine pulling water from the lake, when the pump stops, I could hear and feel the water being sucked from the pump and out of the unused open zone, and pump will need to be primed again. I could send a video of the "phenomenon" if necessary.. Boca Raton, FL.

[@Proirrigationtraining]

Yes, you definitely need to cap that unused zone outlet. I'm not sure if that's what's causing the loss of prime. If you immediately try to restart the pump, and it's already lost prime, then yeah that's what it is. But if it takes a while to actually lose the prime, then it's probably the foot valve leaking through.

[@slowrider30]

Look up a "check valve" you should have one from keeping the water primed at the pump.

[@Proirrigationtraining]

@@slowrider30 Yessir, that's right. I know a lot of lingo is regional. When I said "foot valve" I meant to imply there is a check valve with screen on the intake of a lake pump setup. Thanks for pointing that out. That's what's holding your water in the pump for it to self prime. If it's leaking, you'll not have prime next run.

[@michaelgracewood5893]

I have a 4 zone K-4000 configured for 2 zones that has worked for years. Now it is spraying water from underneath the body of the indexing valve when activated for either zone. Any ideas or suggestions? I assume that I have to replace the entire body.

[@Proirrigationtraining]

I'm so sorry that I didn't see your comment when it was made. I'd reckon that you've replaced the valve by now. Probably a crack on the underside?

[@arnoldrodriguez3803]

So I have 11 zones in my system. My system runs off of a shallow well with a 2 Hp pump. System comes on fine with timer and works great until it reaches zone # 8. At that point pressure drops dramatically in zone #8 and only a small stream comes from one or two of that zones heads. I then go to my well pump and crack the threaded bleeder on top of the impeller housing. air bubbles will then come out and within a minute or two zone #8 will pressurize and come to life. The system will then finish off the remaining watering cycle without a hitch. Next day this same problem will repeat. What might I check in my system? Thanks

[@Proirrigationtraining]

To be honest, I really don't know about that one. There is a possibility that at zone 8, you're exceeding the refresh rate of the well, and that's possibly causing some air in the line. Try splitting your program in half, run 6 zones one day and then 5 the next.

[@arnoldrodriguez3803]

@@Proirrigationtraining thanks for your response. In the past I’ve always run all 11 cycles without issues until recently. Last night I left the bleeder plug in the pump impeller housing cracked open for the entire watering cycle. The system ran fine even though the bleeder dribbled a small amount of water. However when it reached zone 8 it repeated the same issue. Only two heads sprayed water and only at about 30 % normal volume. I did nothing and watched as the bleeder self purged the air, after about three minutes the sprinklers came on full at 100% and the remaining cycles finished out their cycles as well. Leads me to believe that zone 8 might be taking in air from a sprinkler head when not in use.

[@Proirrigationtraining]

@@arnoldrodriguez3803 That's interesting that it always happens on zone 8. If the valves are easy to get to, you might should rebuild that valve and see if it's causing the problem. I would think if it's a problem with refresh rate or something about the well, it would probably vary a bit when it happens.

[@pmhum]

I have low pressure to just one zona. I think you skipped explaining this question. What causes this? Whats the solution?

[@Proirrigationtraining]

There's a couple things that could be going on. Has the low pressure only started recently? If it has always been that way, it's possible that you have a flow demand that's too high, count up your nozzle flows and check that total against a Friction Loss chart for the pipe size. It could be a blockage in the valve, take it apart and clean and flush all components. It could also be a leak happening on the zone pipe that you haven't detected yet.

[@pmhum]

@@Proirrigationtraining Thank you. That is very helpful.