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Discussion in 'Irrigation' started by No Rush, Sep 9, 2010.
That is how i WOULD DO IT. tHEN DO YOUR TIE IN AND retest it.
Ok, just realized tie in is done. whats currently on the system side of the pvb?
i'll be out there today, take pictures of the gauge on both sides of the PVB, even run the water to see the pressure drop; report back this evening.
Are you irrigating the whole park?
Are you going to use rotors that require 50 psi to operate?
You have learned one of the first rules of being an irrigator. DONT BELIEVE ANYTHING THE CITY (or anyone else for that matter) TELLS YOU. Check for yoself.
Seriously, I've had to argue to the death with numerous purveyors about meter tap blockages, water leaks (mine or theirs) meter issues, meters overbilling, meters with low flow etc. I would trust nothing that they told me without verifying myself.
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That should be what you are testing anyhow. Dynamic pressure is the number you need to do the design.
The pressures the city reports are more of a goal they shoot for or design for. Think of the city water system like a huge sprinkler system with lots of valves opening and closing all the time. Just as the operating pressure in your sprinkler system will change as valves open and close (and as things wear out, like head seals and diaframs) the operating pressure on the city water system changes.
Never use someone else numbers, do you own measurements.
Static pressure is a ball park figure anyway. As Kiril said, you should be thinking about dynamic or operating pressures.
Listen to Sprinkus. Rotors with a 55psi static pressure will not work our well for you.
A pvb will drop 2-5 psi from the check and internal parts inside..
So yes you will have a different psi reading from tc# 1 vs tc#2
Update - the 1.5" irrigation meter is 518' from the 2" PVB with a 2" SCH. 40 main line connecting the two; the meter is connected to a 6' city water line most likely by 1.5" poly (that is what they use for water taps here). Now, I went out today and checked the static and dynamic water pressure at the PVB and took pictures. Here is what I got using two different gauges:
Static 1: 66 psi
Static 2: 68 psi
Dynamic 1: 56 psi
Dynamic 2: 56 psi
While running a zone I also opened the #2 test port on the PVB and the dynamic dropped just alittle more on both gauges to 52 psi.
Next I did all the same tests except i put the gauges on the #2 test port and the dynamic readings were lower 52 psi / 48 psi.
Now, I have designed the new system at 55 PSI (static); have a looped sch 40 2" main line with the PVB only about 1-3 feet from the meter. The rotors i am using only require 35 PSI to operate. From the readings at 518' away I should have plenty of water available. The largest zones are only running 35 GPM a zone.