wrote in message
...
Yes I did look at some of those web sites for the calculations.
However the problem is I have two runs that serves different parts of
the yard and I have yet to discover all the heads and there are areas
that the two runs partially overlap and I do not know which head is
from which run. I fixed a few heads last weekend and once they are
fixed I then realized I have another stretch somewhere else that when
along the perimeter of the property line then under the driveway and
back up on the other side of the sidewalk.

So what I am trying to say is it's impossible for me to know all the
heads and all the run and branches at this time without me digging
them all up, so I am trying to use the best judgment I can to fix a
partial section of it by knowing that the existing configuration works
so trying to isolate the subsystem and establish it's boundary
conditions. The water supply is from a well pump.

MC

I would think your best plan would be to repair the system using your best
information from the existing heads and pipes. Then try it out and figure
out what needs to be changed or added. I have done that a couple of times
and it worked for me. Oversize pipes or sections of pipes do not cause any
problems.

Don Young