Hi PAW,

Your system description is a little unclear, but it is of no concern unless you're overtaxing your system with not enough flow or pressure. Your drip tape operating pressure limit governs which pressure regulator limit you use. Usually this is 25 to 35 psi(then you have to make sure your flow is adequate). Your pressure regulator should match that if your static mainline pressure is very much higher. Do you know your main pressure? Some regulators have a single pressure range and others have an adjustable range(house PR). To clear up your description specify the size and length of your mainline, mainline pressure, mainline flow, length of 1/4" lines, spacing of emitters and flow rate of emitters.
Are your emitters punched into the 1/4" lines? Pressure regulators are fairly cheap if they are small(low psi) What about filters for those line? JMHO Aloha

Ok, let's see if I can clear things up a little without making things worse.

We are setting up 9 4'x8' planter boxes spaced out in a 3x3 grid. My intention is to run 3x 1/2" plastic drip feed lines to each row of 3 boxes. From spigot to first box in each row is approx 25' of uninterrupted pipe. Each of the 3 boxes will contain 32x 0-6gph adjustable bubblers feeding into the 1/2" line via 1/4" micro line ranging in length from 18"-30". My intention was to punch into the 1/2" feed line at 6" intervals and then tee off the 1/4" lines so I would get 32 1/4" lines for each of my 16 connections.

The main lines will then pass under a 3' walkway and then enter the next set of 3 4'x8' boxes where the next 32 emitters will tie into the line in the same manner. Then another 3' walkway followed by the final 3 4'x8' raised planters and their emitters.

Total number of 1/2" lines will be 3, each with their own timer. Total length of each of 1/2" lines will be approx 55'. Total number of drip line connections on each 1/2" line will be 48, and total number of emitters will be 96 @ 0-6gph.

Father-in-law tells me the mainline house pressure is 60-65 psi but I have not tested it at the spigot so I will have to take his word for it.

I know this probably sounds like a lot of emitters for each box, but that's the way the wife wants it. She wants to be able to dial in the water for each 12" square. In actuality, we will probalby only be using 90% of the emitters at any one time due to harvests and crop rotation.

I'm reading that 1/2" drip line will flow about 240gph before it's maxed out, so even if we had all 96 emitters flowing at 2gph my basic math skills are telling me we should be good to go. We're only looking to cover 12"x12" sqaures so there is no need to open up the emiiters anywhere near their max capacity.

And yes, filter & anti back sihpon are also figured in and will all fit in a self-contained box with the timers and fertigation unit.

appreciate the reply

Brett

Brett,

Lets start. You have good info I hope. Find out your main line flow. Are you taking water off the house hose faucet. Test it with a hose pressure gauge you can buy for $10 at the hardware store. Faucets are usually regulated for house pressure by a pressure regulator in the garage. Do have one? If you do, your pressure will be around 45 to 50 psi so as not to harm your water using features in your house(still good pressure). Get a 5-gallon bucket, fill it and time how long it take to fill. That will give you your gph rating. For the 25 ft main, it is better to error on the side of a larger pipe because it is not much more expensive to get a 3/4" or 1" mainline(less noise). The problem is that the water has to travel very fast to meet your water needs in a small diameter pipe and automatic valves will cause water hammer in your house and make a noisy system. Larger pipe, less velocity in the line. If your F-I-L is correct, you have good pressure. It won't matter much because you will use an in-line pressure regulator for the 1/2" poly lines. Flow and velocity is what you now can concentrate about. 1/2" lines are okay to go through the beds(again if you can bigger is better). Are you planning to run all lines at once or one at a time. You will demand 192 gph. You should be designing for 80% of capacity of what you get by the bucket method. Per the 240 gph max for 1/2" line means you are maxing the velocity at only 2 gph per head when your system can go give more if you need it. Just by going to 3/4" or 1" line( not much more cost)and slow the velocity down not to stress your system. The flow will split into your 3 ea. 1/2" lateral lines with less stress. Check your flow! JMHO Aloha

Ok, I think I'm with you so far. I will work on obtaining psi and gph numbers next week when I'm back out at the property.

Yes , setup will run off the yard faucet on the back of the house. I'm already setup to go 3/4" from the faucet, thru the filter, siphon breaker, etc., up to the inlet of the 3 timers. However, from the timers out I was planning to use 1/2" as I headed out across the yard.

Are you saying it might be more beneficial to go 3/4" across the length of the yard with my 3 feed lines and then tee into 1/2" lines to feed each of the boxes?

Brett

Brett,

Yes. Aloha

I wont make it so complictaed for you. I install irrigation , and what you need is to install a pressure regulator 25-35 psi at the valve then run your poly line and then add your emitters.try to stay away from the home stores, you can purchase better quality products at an irrigation store. Try Ewing, Horizon,or look in your local phone book. Good luck!