On Wed, 02 Nov 2011 10:30:19 -0400, blueman wrote:

Larry Jaques writes:

On Sun, 30 Oct 2011 22:25:39 -0400, blueman wrote:
So it seems like the 1/2inch air hose and 1/4 inch fittings (at both
ends) were insufficient to supply enough pressure to maintain 55 psi
through the irrigation system. I guess this makes sense since the
irrigation system itself has 1" diameter pipes and the heads probably
let through a lot more air than the 10 gallon/minute of water that it
does when driven by water.

I'm betting on the regulator being your bottleneck. If you're running
90psi normally, the 115 shouldn't be a problem, as it won't be that
high for long.

It's a cheap regulator (Harbor freight). So if I understand you
correctly, you are suggesting that the regulator limits the volume
significantly and may be the problem here?

I'm saying A) that you probably don't need the regulator at all and B)
that they absolutely can have a secondary function as a flow reducer.
First, run it all the way up to full pressure and check the run time.
Then eliminate it and see if your flow changes. I'm betting that it
will.


I was hesitant to run it higher than 60 since people always warn against
using high air pressures in pvc pipe. Is high air pressure any more
damaging (in the non pipe burst case) to irrigation control valves,
irrigation heads, and backflow preventors then an equivalent water
pressure? (I would think not but just checking)

90% of it is underground and you already use 90psi water, so the
difference is minimal. I'd wear eye protection in any case.


It might have been more evident at the full rate, without the
regulator. You could always fill and try it again to see.


Still, I am a bit hesitant to put that pressure in the irrigation pvc
pipe and fittings...

OK, then don't. shrug If you don't feel it's safe, don't do it.
That's your option, and don't let anyone tell you differrent.

I wouldn't hesitate on my own system, but it's drip irrigation and I
open the far end of the 1/2" poly anyway.

--
Knowledge speaks, but wisdom listens.
-- Jimi Hendrix