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.



wrote in message
oups.com...
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.

TIA