Low Pressure in Sprinkler after starting

[kkeen44]

I have seen a couple of post about this issue but haven't seen a solution. My sprinklers start off with great pressure then after a couple of minutes the pressure drops. I am running a well with a 1HP pump, 15gpm tank. I have 6 heads on the zone. The pressure is 40/60. The tank sits at 60 with nothing running. When the sprinklers kick on it drops to 40 then after a few minutes it drops to 20 and stays there until the zone cuts off. When the zone cuts off the pressure jumps back to 40 and quickly returns to 60. I don't have any signs of a water line leak. What could be the issue?

 

[Jeff H Young]

cap off the 6 heads open valve and see what happens that will settle question leaks easy enough to do.. cap 2 heads see what happens? also has it ever worked right?

 

[Sponsor]

 

[WorthFlorida]

What type of pump? if this if for irritation only, pressure tanks are not needed. Your expediting pressure to keep the tank pressurized.

1 hp is small for irrigation. 1.5 or 2 hp Is preferred. Do as Jeff suggested. It could be the well cannot recovery fast enough with six zones, reason for low pressure after a few minutes. What type of sprinklers are there?

 

[kkeen44]

Thanks for the information. To add a little more to the conversation. I tested it tonight and the issue with the pressure appears to only occur with one of my zones. I tested the other zones and the pressure never dropped. It only happens with this one zone. I did notice today when I dug up one of my sprinklers that a lot of water was running down the sprinkler as it was running. I checked another sprinkler on the same zone and it was doing the same. I am going to replace all 6 sprinklers on that zone to see if that solves my problem. I may be leaking a lot of water from the sprinklers.

 

[kkeen44]

Also this pump is my well for my house. When we put it in we ran lines for the different sprinkler zones. It works fine with my other zones. It appears to only occur with this one zone.

 

[WorthFlorida]

There is a crack pipe or joint leaking. Run the zone until you see water puddling. If it was a sprinkler water would be gushing up.