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Starting Member


Tuesday, April 15th 2008, 1:02pm

how many heads per zone

I have a system I am gonna hook up to a well. The well will only be supplying the sprinklers, I have city water for rest of house. I have RainBird spray heads 1804 with VAN nozzles with 15' radius. I measured 62 psi out of well, and 10 gpm. When measuring gpm I did so through a 5/8'' garden hose. The well is disconnected so all I did was put a fitting on 3/4'' copper coming out of holding tank and attached hose to that. Would my gpm be higher if I measured direct from 3/4''? I plan on using 1'' for rest of system. As of right now I am only able to use 3 heads per zone at 360 degree setting for head. Does my gpm to psi ratio sound correct? Any help is greatly appreciated!!


Supreme Member

Posts: 3,883

Location: Metro NYC


Wednesday, April 16th 2008, 10:47am

You might get better performance with 15F nozzles on the 1804s - 3 15F nozzles are going to draw over 11 gpm, so your mileage may vary.

Lakeside (can't login)



Friday, April 18th 2008, 11:57am


You might get better performance with 15F nozzles on the 1804s - 3 15F nozzles are going to draw over 11 gpm, so your mileage may vary.

I just finished a well system at 10gpm with pump pressure at 60 and house pressure 45.

I used RB 5004s with 2.0 nozzles. I used 4 heads per zone which at 35 PSI runs about 2gpm per head. So a total of 8gpm per zone. I didn't want to strain the well. I also calcuated the PSI lost down roughly to 35 PSI.

With the 1804s, I used the 12Hs. I factored about 1gpm at 35 PSI per head. I used 7-8 per zone.

Works very well. Until the well is established, I put a 5 minute delay between zones just to cover any loss.


Monday, April 21st 2008, 1:54pm

Here is the most important part of designing with a well. You want to turn the pump on ( when the valve opens) and you dont want the pump to turn off till your done watering. for example say you only had one head and it ran at a rate of 2 gpm. A well has a pressure tank and the effect onf one head would be that the pressure would start to drop and use up the supply of the pressure tank and once its down to about 40 psi the pump would kick on and refill the pressure tank then the pump torns off and the cycle repeats itself. this Cycling is harder on the pump than constant running.

If I were you I would design my system based on 10 gpm and it should work out fine.

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