SPRINKLER TALK FORUM - You Got Questions, We've Got Answers

Quoted from "Mitchgo"

The mp rotators are touchy with water pressure and flow.

What's the technical aspect you're getting at with the word 'touchy?'

I'm new on here, so please don't presume too much knowledge. I do
have some minor experience, but only with above-ground set-ups,
most of which are sprinklers, including micros.

You just need an adequate amount of water pressure and supply. With out it, they don't work well at all

Quoted from "Mitchgo"

You just need an adequate amount of water pressure and supply. With out it, they don't work well at all.

OK - thanks. Their tolerance for pressure/flow drop
is poor. In your experience, presuming good volume/
flow, what's optimum? 2 or 3 bar? (Or higher?)

Why not do some testing of your supply, and not have to guess about your design?

It was the sprinkler head performance that my question
was aimed at. I'm familiar with the supply pressure
options of the existing system. The present water use
devices are optimum at 2 bar. Or close: a little higher
is better than a little lower, generally. Significantly
higher pressures give more misting and 'atomization'
with concomitant loss to wind drift - impact sprinklers
being the worst affected. The same supply is used
for five household's domestic supply, so much below
two bars can be a dilemma for showers, ceramic
mixer tapware and such.

I had a system put in by an installer. But the pump delivers more than he anticipated!
I think he 'allowed' for more losses and a bigger margin-for-error than proved necessary.
That's brought on some interesting consequences.

So I have a question about controllers.

The installed system uses a Hunter geared sprinklers and a Pro-C controller. As far as
I can tell, the controller can't switch more than one station, unless wired in common.
To 'make use' of the surplus water capacity, (to keep the pump from cycling on & off)
I want to integrate other existing zones (stations?) into the newly-installed system.

But that requires running several zones/stations for uncommon times. I.e. Run zone 7
for 6 hours continuously, while running the other six zones concurrently with zone
7, but one at a time.

E.g. zone 1 plus zone 7 for one hour, zone 2 plus zone 7 for the next hour, zone 3 plus
zone 7 for the next hour, and so on. (That's needed to compensate for the lower pre-
cipitation rates of the micro sprinklers in the existing zones to be added.)

Am I right in assessing the Pro-C as unable to do that? If so, what alternative controller
would do what's required? As the system expands, I don't foresee more than 12 zones,
in total.

Or is adding another controller the best way to go?

What prevents you from changing the nozzles in the sprinkler heads, to match zone flow to the water supply?

AFAIK, already at the top of the range. Evenness of precipitation
across the installation may also be a factor. Plus it makes sense
to add in the extra zones, now that there's more water than the
designer thought would be available.

What application is zone 7 and why do all the zones need 1 hour run time? It's pretty rare to actually need that much run time IMO

The 1 hour figure was for illustrative purposes only.
Zone 7 needs to run for whatever duration is the
aggregate total time of all the other zones.

Dan 2001 micro sprinklers @ 70 lph ea , covering long
strips of garden, under big and thirsty trees. By the
time a few others are reckoned, about 1000 lph for
zone 7, give or take a bit. Those micro sprinklers
seem quite tolerant of pressure fluctuations, too.

It's looking like running another controller might be
the most workable solution. The installer is making
a return visit, in a couple of days.