On Sep 9, 8:09*am, 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 hehttp://forums2.gardenweb.com/forums/...341731539.html

Thanks,

Ray

First question is, what's wrong with the 1" section that runs under
the sidewalk now? Usually this pipe lasts virtually forever, unless
it gets damaged. Unless there is evidence that it is all failing for
some reason, then I'd just leave the section under the sidewalk and
use it.

Second, any irrigation company that tells the homeowner they have to
remove the paver sidewalk is being run by idiots. Any decent
company has the eqpt to easily get a 1" pipe under a sidewalk. They
use a driving tool that is powered off an air compressor and do it
every day to cross 20ft driveways or more.

In your case, that span could also be crossed by hand, using a steel
driving pipe and sledgehammer without very much difficulty.

The 3/4" pipe solution for the sidewalk could be OK. Besides the
number of heads, it also depends on how many GPM the heads. But I
have to wonder. Will 3/4" pipe fit thorugh 1" pipe? Would seem to me
it could be a close fit.