another sprinkler system question

[larryz]

I had a sprinkler system installed last summer. I only have a total of twelve heads with three per zone (4 zones). Only one zone runs at a time. It seems to me that after the system runs for awhile that the water starts surging. You can see it visibly plus you can hear it in the lines in the house. What would this indicate?

Thanks!

[Surface Tension]

Is your well pump turning on and off? I say it is and the air bladder in your pressure tank might need to be charged and even the cut in pressure adjusted.

Your pump should run continuously when watering the lawn.

Instead of running one zone, run two or more till you get to the point that the pump runs constant. So as an example if the cut in pressure is at 40 and out at 60 then get to run constant in between.

You might find this thread useful with more details in correctly adjusting the pressure switch.

[setterguy]

You can also try and adjust the size of the nozzles until you get your pump to run continuously throughout the cycle. Sometimes 1-2 gallons per minute difference will do it. You will want to address this quickly as you don't want your pump kicking in and out all the time. If you had it installed the contractor should be able to help you with this.

[MuleShack]

You can always go inside your control box and move the wires for zones 3 to the zone 1 screw and then zone 4 to the zone 2 screw.

This will allow 6 heads to run at once, which is a pretty standard number provided you have enough flow to run 6 at a time.

[larryz]

Maybe pulsating would have been a better word than surging if that makes sense. Would that make any difference in the suggestions/recommendations? It is very rapid about like the second hand on a clock.

I am having a bit of a struggle getting him out here. I think that they are pretty busy right now. It is a new (last fall) system.

Thanks for all the input.

[MuleShack]

You didn't specify if it was a well system or city water?

The replies were addressed to a well system with the well pump causing the problems.

If you are on city water, then it is a different story.

When you say pulsating, does it do it for all the zones? or just one or two zones? Are you running any other water when the irrigation is going?

[MuleShack]

Did you check the valves on the BPV. They might still be only 1/2 open which might cause a surge in the valve??

[larryz]

Sorry I was not more descriptive. Yes it is a well with a pump supposedly sized large enough for a sprinkler system. We typically do not run other water at that time. Yes it seems that the pulsating occurs during the third and maybe the fourth zone. I will check that the next cycle. And sorry I don't know what the BPV is.

Thanks for all the input.

[MuleShack]

back flow valve outside of the house. When the blow it out, they turn the valves half shut, so it could be restricting flow if they were not opened fully this spring.

[KLoopBinaction]

Funny they put 3 heads on a zone, must have a flow or gpm issue to begin with, I'd try to nozzle down once should help. combining zone will not resolute.