My house came with about 10-12 sprinkler heads connected to one zone
for the front lawn. It is close to the water supply (at driveway),
even though most people would say there is too many heads.. It used to
work somewhat reasonbly. I only noticed one or two heads not popping
up, couple months ago.
Today I noticed about 4-5 of the heads that are further down stream,
are not popping up. I removed one of these heads and let the water
run, and the pressure is weak on those head locations. It seems like
the pressure suddenly dropped somewhere in the system, causing the
heads downstream to no pop up.
The main question I have is that when I turn the knob of the valve,
after a turn or so, the water flow does not appear to increase, is this
normal, maybe the valve is damaged and I'm not getting full flow. (I
have been turning the knob a bit)
Or I might have a crack somewhere, I do not know the routing of the
system so I might have to dig around a bit.
I also wondered if there was a rock/debris or something stuck in the
system. Which I might need to unearth the pipes to check
Or perhaps the water company doesn't have enough pressure lately?
Which should I look into first?
I wanted to do a complete re-installation using bigger pipes eventually
and less heads, but if I fix this I can wait until next year.
1) 10-12 sprinkler heads ... way to many... But we
don't know your water source pressure...
2) Have you cleared water out of your sprinkler system
before the winter.
3) You probably have crack, so start digging btw the last
that has pressure & and first that doesn't.
Run it for awhile and follow the pipes, try to feel with your feet any
extra wet area that may be leaking. often a head or pipe can crack at
the base allowing a leak, look for puddling at head bases. Remove the
last few heads and check-look inside for dirt-obstructions, and run the
line to try to clear it, Probably a crack somewhere in the pipe. Yes the
valve could also be bad.
I started closing the screw on the nozzles of each head so hopefully a
leak might show up, no luck, then I started pulling the nozzles off a
head and starting the system one by one, I have found a node that shot
water 4 ft high (good pressure) but the next node only bubbled 2"
high. I might have narrowed down the huge pressure drop location..
I'll unearth the between those connections and see what is up.
Does it hurt anything, like the valve or solenoid, to close the
nozzles and pressurize the system like that?
email@example.com (m Ransley) wrote in message
I have about 70 lbs static head pressure here, and I have about 10 sprinkler
heads per circuit. No problems at all. More sprinkler power than I need.
Of course, I have many heads in a small lawn, necessitating attenuation of
spray pattern at each head. If I had 10 sprinklers, each blowing at full
throttle, then I might see some "droop" in performance.
I believe I used 3/4" sprinkler pipe, instead of 1/2", but I cannot be sure.
3/4" has far better conductivity than 1/2", so I'm not losing much "spraying
power" to friction in the delivery piping. Futhermore, as I said, each of
my sprinkler heads is constricting the water flow, so I don't have a
"virtual hemorrhage" at any one sprinkler head.
If you have a crack, that's a hemorrhage, which will attenuate the pressure
available at each sprinkler head in the circuit, both upstream, and
especially downstream. This difference will be more noticeable if your
distribution piping has high impedance pipes...meaning skinny or obstructed.
That's a hint on "where to dig." You can thereby vector your break, by
observing your sprinklers...and by looking for a puddle!
For starters, remove all sprinkler heads and blow debris out of the system.
If you've got roots in the system, they won't blow out. Watch for patterns,
and clear roots where conspicuous.
You'll also need a pressure gauge, to measure your head pressure. There is
"static pressure," and "dynamic pressure." Each will tell you plenty. You
might not have to do a ton of work, if you finesse this problem. I say 70
lbs static pressure is enough at the sprinkler valve, provided that you have
a good main line from the utility's meter. My pipes are in excellent
condition everywhere, which might justify why I can put so many heads on one
circuit. I have one circuit with dozens of drip-irrigation heads and
bubblers on it. I don't let any one bubbler deliver too much water.
I have a bag full of caps I can screw in place of the sprinkler heads. I
cap off all the sprinklers and turn on the water. If there is a bad leak it
will usually result in a gusher somewhere in the yard within a few minutes
(nice part is that it excavates the hole at the same time). If no gusher, I
start at the furthest head and flush the system. Cap off that head and move
up to the next. This procedure will help localize an obstruction.
You may be able to clear an obstruction by reverse flushing the pipe. Cap
off all heads except the first and last. Attach a garden hose to the last
using an adapter and turn on the water so it flows out the first head
(opposite normal flow in pipe). Inspect each sprinkler head for root
intrusion or insect nests.
Bigger pipes will cut down on chances of obstruction and allow more water to
flow to the heads but it will not necessarily help with a low pressure
problem. Fewer heads per circuit definately will help with pressure and
allow you to program a more effecient use of your water.
I have a timer operated sprinkler system parts of which are 40 years old.
The older parts used that plastic pipe that came in rolls -- ABS?, -- not
the modern polyethylene. I have frequent failures that are characterized by
the gradually diminishing flow that you observed. These are almost always
the result of a pipe which has split to allow gradually increasing leakage
and loss of pressure at the heads..
Sometimes the solenoid valves fail, but that usually results in a sudden
reduction of the flow to the sprinkler heads.
The pipe leaks are sometimes hard to find. In my case, it helps that I know
the routing of the pipes. It could be tough otherwise. As others have
said, you first look for overly wet spots above the failed pipe. --- SJF
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