Question
QUESTION: Zone 4 of my sprinkler system has 6 Hunter MP rotator heads.  2 of the heads are MP3000 90 deg, 2 are MP3000 180 deg, 1 is MP2000 360 and 1 is MP2000 180 deg.

Each of these heads requires at least 25psi to operate according to the Hunter website and the total flow demand for that zone is 6.54 GPM.

The mainline is 1" CL200 pvc and each head is a one-off from the mainline with 1/2" CL200 pvc.

I've attached a pressure gauge in place of the farthest head and read ~20psi while running.  I inlined a pressure gauge right before the zone 4 valve, and measure a static pressure of ~55psi and a running pressure around 20psi.

The sprinkler heads don't seem to be reaching their full radius arc and occasionally have trouble popping up.  The recommendation I received was to split it into 2 zones which I'd rather avoid unless absolutely necessary.

What I am trying to understand is if there is a problem along the way to the head[s].  Thanks.

ANSWER: Hi Jon,

Try, first, replacing the rotors nozzle. Install ones with less GMP rate. Lets say you have a 6.0GPM nozzle in each head you are trowing 36GPM if you replace for ones with 2.0GPM you will thrown 12GPM in total. The Maximum GPM rate for a 1" PVC pipe is 18GPM so you need to stay at total GPM below 18GPM.

Good luck
Guillermo

---------- FOLLOW-UP ----------

QUESTION: The GPM of these heads is very small (http://www.hunterindustries.com/products/mprotator/).  The total for the entire zone is only 6.54GPM so I don't think I have exceeded the maximum GPM for the pipes.

ANSWER: Hi Jon

Does you have independent valves for each zone? the electric ones? if so check the valve to make sure the flow control is not closed. Open it all the way up, if this does not work check the
pipe for leaks, also check the valve inside for obstructions, clean it carefully, check the diaphragm and replace it if looks bad. Also replace the selenoid.

Does the others zones work fine. what is the water source?

Good luck
Guillermo

---------- FOLLOW-UP ----------

QUESTION: There is an separate valve for each zone.  It has a solenoid to open/close it.  I am manually opening and closing the valve though for these tests.  Also these valves don't have a flow control knob.

This is a brand new system but I'll check inside the valves just in case.

If everything is working properly, shouldn't the dynamic pressure right before the zone valve measure approximately the same as the static pressure when the zone valve is closed or am I missing something?  In my case it's dropping from 45-55psi to around 21psi.

Thanks for the replies.

Answer
You have a pressure loss of  20-24PSI. This is normal. You says the system is brand new. When the system was designed was done the pressure loss calculations? I mean all this aspects was considered:

- Water Meter
- Backflow Preventer
- Filter (optional) Usually 2 PSI - check for loss value with the manufacturer.
- Mainline
- Valves
- Elevation change (change in feet x .433 = PSI)
- Sprinkler Heads or Drip Emitters
- Lateral Pipes (maximum is 20% of sprinkler head PSI above)

- Total Pressure Loss (add together the values above)

If you don't have any leaks or broke pipes with only 6 sprinklers the zone should work fine. The other zones work fine? are those also on 1" pipe.
If you can send me all the details for your system I'll be more helpful

Thanks
Guillermo