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Author:
SwimRunPlumb (MI)
OK, who actually KNOWS, and is not just guessing, on what the truth is about increasing irrigation lines off a 3/4" line to 1" to go outside to feed the vacume breaker.
I have heard conflicting reports. Is there any benefit to this when it passes through a 5/8" meter. Once the flow is reduced, does it do anything bumping it back up to 1". I have had guys tell me you have to bump it up as soon as possible, and others have said it can be ran entirely in 3/4 and it won't matter.
What is it?
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Author:
hj
It depends on the length of the line. Friction loss decreases as the pipe size increases and the velocity of fluid through the pipe decreases. So a short small pipe will deliver almost the same as a large short pipe if the volume demand is not excessive. BUT, once the pipe length, or volume demand, starts increasing the flow from the smaller pipe will fall behind that of the larger one.
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Author:
jimmy-o (CA)
This is neither secret nor rocket science. When we are talking irrigation, we are often talking quite long pipe runs. Pressure LOSS in a pipe is directly related to both the size and length of the pipe.
Assuming at the start that you have a meter connection that will deliver the gallons-per-minute that you need, then it boils down to delivering that gpm to the yard. If you have a quite long run, it makes perfect sense to use perhaps 1" pipe for the main line back to a manifold, and possibly 3/4" for some of the long laterals.
On line, all the majors like Orbit, Rainbird, and Toro have free sprinkler design services. Many irrigation supply houses will also do that. When you get your plan, you will see that when appropriate, it incorporates the sizing techniques I have described.
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Author:
SwimRunPlumb (MI)
I am only talking about coming off the water main somewhere to go to the outside to feed the vacume breaker. I am not talking about the sprinkling lines.
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Author:
hj
The same principle applies. If it is a short run, the size MAY not be a factor as long as it is not REALLY small. As the distance increases the size of the pipe MAY also depending on many factors which will be unique to your installation. You have to consider that the "sprinkler pipes" ARE part of the equation.
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