Two of the five heads pop about 1/4 inch, instead of the full 4 inches,
and dribble a small amount of water. They happen to be the lowest ones,
but the lawn's slope is really pretty gentle, maybe five degrees.

In the room containing the water meter and the main shutoff valve, I can
hear the water running to the bad zone. I timed how long it takes for
the water meter to move a certain amount. The 14 seconds the bad zone
takes is in line with the 14-19 seconds the other four zones take. This
rules out a partially opened zone valve and a blockage in the pipe run
between the zone valve and the head nearest it. It does suggest a break
in that run. What's puzzling is that the water would be absorbed in the
heavy soil surrounding the break at the same rate that water would leave
the five heads if there were no breaks.

The 3/4" pipes are about 8 inches below the surface. I've let the water
run for over a half hour, but couldn't detect wet spots in the lawn. I
don't know the routing of the pipes, so it's just guesswork where to look.

For what it's worth, last year was the first time (in five years) that I
ever had the system winterized by hiring someone to blow the water out
of the pipes. (I'm in New Jersey.)

Any suggestions for locating the break?

Thanks,

Ray

According to Ray K :
Two of the five heads pop about 1/4 inch, instead of the full 4 inches,
and dribble a small amount of water. They happen to be the lowest ones,
but the lawn's slope is really pretty gentle, maybe five degrees.

In the room containing the water meter and the main shutoff valve, I can
hear the water running to the bad zone. I timed how long it takes for
the water meter to move a certain amount. The 14 seconds the bad zone
takes is in line with the 14-19 seconds the other four zones take. This
rules out a partially opened zone valve and a blockage in the pipe run
between the zone valve and the head nearest it. It does suggest a break
in that run. What's puzzling is that the water would be absorbed in the
heavy soil surrounding the break at the same rate that water would leave
the five heads if there were no breaks.

You'd be surprised at how much water can disappear. It's coming out
under pressure, and if the jet is _downwards_, it may be building its
very own sink hole. If the jet was _upwards_, you'd probably have
a geyser.

Before starting to rip anything up, try removing the heads themselves. The
strainers may be plugged with grit. Them being the lowest ones is
suggestive.

Are the slow heads adjacent to the valve, or the t'other end?
--
Chris Lewis, Una confibula non set est
It's not just anyone who gets a Starship Cruiser class named after them.

Ray K wrote:
Two of the five heads pop about 1/4 inch, instead of the full 4 inches,
and dribble a small amount of water. They happen to be the lowest ones,
but the lawn's slope is really pretty gentle, maybe five degrees.

In the room containing the water meter and the main shutoff valve, I can
hear the water running to the bad zone. I timed how long it takes for
the water meter to move a certain amount. The 14 seconds the bad zone
takes is in line with the 14-19 seconds the other four zones take. This
rules out a partially opened zone valve and a blockage in the pipe run
between the zone valve and the head nearest it. It does suggest a break
in that run. What's puzzling is that the water would be absorbed in the
heavy soil surrounding the break at the same rate that water would leave
the five heads if there were no breaks.

The 3/4" pipes are about 8 inches below the surface. I've let the water
run for over a half hour, but couldn't detect wet spots in the lawn. I
don't know the routing of the pipes, so it's just guesswork where to look.

For what it's worth, last year was the first time (in five years) that I
ever had the system winterized by hiring someone to blow the water out
of the pipes. (I'm in New Jersey.)

Any suggestions for locating the break?

If you can plug or cap off the risers on the heads that *are* popping up, that
*may* generate enough extra pressure to make the broken head more visible.
Most likely it's a cracked riser, although sometimes the bodies themselves get a
hairline crack. Real fun finding the culprit, even when you know the location
of the heads. Not surprising if winterizing caused the problem -- I've had
heads launched out the ground by yahoos with those big truck-mounted
compressors.

Chris Lewis wrote:

According to Ray K :


Two of the five heads pop about 1/4 inch, instead of the full 4 inches,
and dribble a small amount of water. They happen to be the lowest ones,
but the lawn's slope is really pretty gentle, maybe five degrees.





In the room containing the water meter and the main shutoff valve, I can
hear the water running to the bad zone. I timed how long it takes for
the water meter to move a certain amount. The 14 seconds the bad zone
takes is in line with the 14-19 seconds the other four zones take. This
rules out a partially opened zone valve and a blockage in the pipe run
between the zone valve and the head nearest it. It does suggest a break
in that run. What's puzzling is that the water would be absorbed in the
heavy soil surrounding the break at the same rate that water would leave
the five heads if there were no breaks.



You'd be surprised at how much water can disappear. It's coming out
under pressure, and if the jet is _downwards_, it may be building its
very own sink hole. If the jet was _upwards_, you'd probably have
a geyser.

Before starting to rip anything up, try removing the heads themselves. The
strainers may be plugged with grit. Them being the lowest ones is
suggestive.

Are the slow heads adjacent to the valve, or the t'other end?


No, they are at the most distant end.

Thanks,

Ray

According to Ray K :

No, they are at the most distant end.

I'd pull the caps/strainers out of the two "slow" ones and the one
immediately previous to them and make sure they're clean. This
should include being able to see into the housing to see if there's
something plugging the line.

The nozzles on these things sometimes plug up with grit even
tho they have strainers.

While you have them open, check for frost-distortion. Ie: cracks,
splits, or jammed/seized/bent popups (the popups may be stuck, most
units dribble if they can't get the popup all/most of the way up).

If that doesn't help, put bricks on the operating pop-ups, and
run the line for at least an hour, search for wet spots, and if you
still can't find one, "stomp" [+] along the ground where the line is
most likely to be (between the three heads). Unless it's buried
real deep, you should be able to find any tubing leaks by where
you fall in ;-)

While you have the bricks on the working pop-ups, recheck
your water flow and see if it goes down drastically. If not,
you have a leak. If it does, then you have an obstruction.

If that _still_ doesn't work, you're going to have to start
excavating along the lines. They're usually not buried very
deep, so it's not so bad.

Each leak I've had (two incautiously applied shovels, one
chipmunk) has announced itself by geysers/sinkholes.

[+] a "poker" might work better, but you may end up adding
more holes...
--
Chris Lewis, Una confibula non set est
It's not just anyone who gets a Starship Cruiser class named after them.

Chris Lewis wrote:

According to Ray K :



No, they are at the most distant end.



I'd pull the caps/strainers out of the two "slow" ones and the one
immediately previous to them and make sure they're clean. This
should include being able to see into the housing to see if there's
something plugging the line.

The nozzles on these things sometimes plug up with grit even
tho they have strainers.

While you have them open, check for frost-distortion. Ie: cracks,
splits, or jammed/seized/bent popups (the popups may be stuck, most
units dribble if they can't get the popup all/most of the way up).

If that doesn't help, put bricks on the operating pop-ups, and
run the line for at least an hour, search for wet spots, and if you
still can't find one, "stomp" [+] along the ground where the line is
most likely to be (between the three heads). Unless it's buried
real deep, you should be able to find any tubing leaks by where
you fall in ;-)

While you have the bricks on the working pop-ups, recheck
your water flow and see if it goes down drastically. If not,
you have a leak. If it does, then you have an obstruction.


Thanks, Chris, for the suggestions.

There is a misunderstanding about my configuration. There are five, not
three, heads in the problem zone. The two lowest ones dribble; nothing
at all out of the other three. If the dribbling ones were plugged up
with grit, that would restrict flow through those heads and increase
pressure to the remaining ones, which should then have a greater
tendency to rise and squirt water farther than when all five are
working. Am I missing something?

Ray

According to Ray K :
There is a misunderstanding about my configuration. There are five, not
three, heads in the problem zone. The two lowest ones dribble; nothing
at all out of the other three. If the dribbling ones were plugged up
with grit, that would restrict flow through those heads and increase
pressure to the remaining ones, which should then have a greater
tendency to rise and squirt water farther than when all five are
working. Am I missing something?

I knew there were five, but I thought the other 3 were working normally.

So, to be sure I understand, the string has 5 heads. The first
three (going outwards from the valve) aren't emitting any water,
and the last two are dribbling.

That's suggestive that the valve is defective. I _know_ you're
saying that the water meter seems to indicate that water is
flowing in this circuit, but I find it hard to believe that
a leak would result in the three heads _first_ in the string
get no water, and the last two dribble. The leak
rate would have to be horrendous (as in virtual severing).

There should still be enough backpressure to get _something_
out of the first three.

Unless something like: the first three are MUCH higher than
the valve, and the last two are much lower than the first
three.

If you lay bricks on the dribbling two, do the other three
start to dribble?

I think you're going to have to start considering disconnecting
the line at the valve and check for full flow. Then, secondly,
start excavating around the heads.

[Apropos: after many years of trouble free spring restarting,
I have two zones (off a 6-way controller) that won't trigger
at all, and on the second controller (only runs two zone),
frost had stripped out the solenoid. I'm going to have
to start electrical diagnostics tonite...]

--
Chris Lewis, Una confibula non set est
It's not just anyone who gets a Starship Cruiser class named after them.

I let the water run for about 2 hours. Finally, a very damp spot
appeared. It turns out that the pipe had a six-inch split along its
bottom, about 2 feet upstream of the first head on the zone. I replaced
it, and then a new crack appeared a couple of inches upstream of the
repaired section. Now I have a new job waiting for me on Monday.