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MikeJns

New Member

1

Sunday, July 31st 2016, 11:17am

Normal pressure then drops off

I have a system with many zones. One zone comes on fine, all the heads come on at full strength but within a minute, the pressure slowly drops by half to all sprinklers in that zone (all heads are pop ups). All the other zones work fine. I have run the affected zone for awhile but can not find any wet spots indicating leaks.

Other information to consider, initially in the season, when I started the zone, it was low pressure. After running the zone several times it improved to the current point, great pressure initially that falls off within a minute. If I turn the zone on at the valve manually, the pressure is still at half to the sprinklers and the booster pump does not come on. If zone turned on at control box, zone comes on full strength then pressure slowly falls off. And final note, one pop up sprinkler head seems to spurt a lot more air than the others on the line as the pressure goes down.


Any ways you might suggest that I try to further pinpoint the issue?

Thanks for taking the time to share your expertise!!
Mike

Wet_Boots

Supreme Member

Posts: 5,269

Location: Metro NYC

2

Sunday, July 31st 2016, 12:25pm

city water or well water?

MikeJns

New Member

3

Sunday, July 31st 2016, 12:31pm

Thanks for the quick reply. It is community well water. The pressure at the house spigot is 40 psi.

Wet_Boots

Supreme Member

Posts: 5,269

Location: Metro NYC

4

Sunday, July 31st 2016, 2:24pm

If you have any leak in the supply line, the booster pump can suck water and air back into that line.

Just on paper, you are not in a comfortable place. If the supply line is not large enough in diameter, a booster pump can create a vacuum, and that can team up with an outdoor leak to draw foul water into your house supply.

MikeJns

New Member

5

Sunday, July 31st 2016, 6:09pm

Again, Thanks for the help in your response. So you think the supply line is too small? This system is 30 years old. No issues on other zones with air or the like. This troubled zone has 8 pop up heads the the other zones have may 5 heads max but are spray heads that reach 30 feet. When the irrigation system is running the house water supply slows to 1/4 of its normal pressure. I do not want to increase the regulator pressure since we already had a pipe burst in house when the regulator pressure was 60 lbs.

Come think of it this issue may have started after I changed the house regulator to 40 PSI but really do not recall timing of all this. Could this be the problem low supply regulator pressure?

So if supply line is too small is there any way to test it? Allot of work to rune a new 100 foot supply just for one zone issue.

Again your thoughts

Thanks for your time in advance

Wet_Boots

Supreme Member

Posts: 5,269

Location: Metro NYC

6

Sunday, July 31st 2016, 7:11pm

You might try different nozzles in the trouble zone. It can happen that replacement nozzles over the years are using too much water, and giving poor performance. There is some newer technology at work in some modern nozzles, should you need "better than original equipment" performance.

Inventory the nozzles used in the problem zone.

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