Rebel1 wrote:
I have to replace about 20 feet of 1-inch black poly pipe between the
house and the five-zone manifold. About six feet of the pipe passes
under a paver brick walkway, which I don't want to disturb. The pipe is
about 6-8" below the soil, in Central New Jersey.

The first sprinkler company I called said the walkway must be disturbed,
and it would be up to me to make arrangements to remove and restore the
pavers. If I tackled that job myself, then I could easily replace the
pipe as well.

The second company said he would simply pass a 3/4" section of pipe
through the existing 1" pipe under the walkway, then use adapters to
transition back to 1 inch. (I don't know if meant to make the entire run
3/4" or just the part passing under the walkway. He's looking over the
job tomorrow.)

I asked about the reduced flow available through the 3/4" pipe. He said
that as long as I don't have more than five sprinkler heads on a zone, I
would be okay. My heads are all pop-ups, mostly rotaries by Hunter, but
a few non-rotaries, and there are only five per zone, so it sounds okay.
One site says that typical head delivers 1/2 gal/minute, so with five
per zone, that's 2.5 gpm, well below what a 3/4" pipe can deliver (about
23 gpm).

Any comments on using 3/4" pipe, or other suggestions for not disturbing
the walkway? One website suggested blasting a hole using full-force
water through a garden hose. Other suggestions are he
http://forums2.gardenweb.com/forums/...341731539.html

Thanks,

Ray

Rebel1 wrote:
As I think more about it, maybe another approach will work.

There is 5 feet of pipe between the house and the walkway, 5 feet
under the walkway, and 12-15 feet more to the manifold.

1. I dig on both sides of the walkway until all the pipe is exposed.
2. I cut and remove the section between the walkway and the house,
and cover the exposed end to prevent soil from entering during step 5.
3. I cut the pipe on other side of the walkway, leaving a 1-foot
"stub," and remove the pipe all the way to the manifold.
4. I connect the replacement pipe to this stub with an ordinary
lawn-pipe connector that slips inside both ends. (I pour hot water on
the ends of the pipe to make inserting the connector easier.)
5. I simply push the new pipe under the walkway toward the house and
cut off the old section after it emerges.

Of course there will be the friction of the soil to overcome. But the
break is under the walkway, so before starting the above, I'll simply
turn on the water for a couple of seconds so the water coming out of the
break will act as a lubricant.

Have I overlooked something?

Ray

Never underestimate the power of two muscular guys. They were able to
snake a new 1" pipe in the same hole as the old one, joining the new
with the old with a coupling, with one pushing, the other pulling. They
arrived at 2:10 and drove away 2:32. Very impressive.

Thanks, again, to everyone for your comments.

Ray