Biddle34- If you will look at the upper left hand corner of my post you will note that I have to date posted more than 2000 replies to questions in this forum. Throughout that time I have always endeavored to provide a complete description of the problem as well as the solution, and in fact, in most cases I have drug out my crayola's and created illustrations to support my text. I am sorry if you find 8th grade math a bit difficult to follow, but i can assure you that based upon the hundreds of direct emails i get in response to my posts, the majority of those reading my answers appreciate the in depth detail.
The reason I did not post a simple answer is because based upon the information presented in the original post, there is no simple question however there is the false assumption that because both the front and back yard systems are attached to the same line, they should have equal pressure, which simply is not true. Point of fact, once flow begins no two points in the entire potable water distribution system in the whole house will have equal pressure.
No matter what we are working on, in order to diagnose a problem we must first determine what should be happening under normal circumstances, then check the system for abnormalities and once we have discovered the abnormality we can then try to isolate the cause.
On the other hand we could take the typical "handyman's" simple approach and assume facts not present and begin cutting and piecing into the system in the blind hope that we might stumbled upon the solution. But then in my experience that method generally introduces more problems than it resolves.
If you will read the last line of my previous post I specifically asked for additional information so that I could work out the details and help them resolve the problem. I could have just as easily just posted a link where the reader can download the RainBird Lawn irrigation design manual and let them work it out for themselves.
So now we have three possible methods of resolving this problem:
1. We could use the HandyMan technique, cut and piece and hope we find the solution
2. Download the 140page Rainbird manual and spend the next month or so studying the details
3. Post additional information and i will be happy to work through the problem with you.
RAINBIRD LAWN IRRIGATION DESIGN MANUAL (140 pages in PDF format)
http://www.rainbird.com/pdf/turf/Irr...signManual.pdf