So I installed a centrifugal booster pump to increase the pressure in my irrigation system with what I was told I was supposed to use and even though the pump is running, I keep losing pressure. It seems like the pump doesn't have enough water send out today irrigation system. Please help me figure out what's wrong.

What size main runs and branches do you have ? How many heads on each branch ? What's the gal/m use per each sprinkler head ? What's the incoming pressure - or pressure you are generating with pump ? Back to you. Milo

Thanks Milo for taking the time. Ok so I'm running a 1" main line and have between 7 and 12 spray heads with pressure compensating rotary nozzles. The incoming pressure fluctuates between 40 And 55 psi depending on the time of the day but the system was design to work with 40 psi.

Booster pumps only work well when there is an abundant supply of water to them. If the supply is limited, then the pump struggles to supply enough volume to keep up the pressure. Are you pulling from a 1" line and pumping into a 1" line?

Yes I am from 1" goes up to 11/4" schedule 40 pipe into the pump and then out of the pump and back to 1"

It is too complicated to explain. Here is a good website that has all the information you need to install properly sized sprinkler system.

Irrigation Design - Landscape Sprinkler System Design Tutorial

But as a rule of thumb:

1. Do Not use 1/2" at all
2. Do not taper your main run
3. Run 1" minimum pipe and all the way to the last sprinkler head
4. If pressure on low side, use "Loop" type installation
5. The lower pressure you have, the larger diameter pipe you should use
6. If low pressure than use less sprinkler heads on each run
7. Do not tap into incoming water from your house. Take water supply from as close to the water meter as possible
8. Run only 1 branch at the time

Read the enclosed website. It is very informative. Let us know how you did. Back to you. Milo

Yes I agree I don't like to use 1/2 " even though u kinda have to if you put it on paper and do the hydraulics for the design. Also I agree on the tapping the closer it is to the meter the better. The only thing is the plumber told us to tap closer to the house, so we did. but anyways the problem is not the irrigation system the problem is with the pump. The system was design to work with a ittle less than 40 psi.a 10% wiggle room which is why we ended up with 12 zones. The loop design works great unfortunately for us the driveway was In the way.anyways back to the pump.
I think JLISENBE has a really good point , I don't think the .1" main is providing enough water to the pump what I don't understand I why I lose every bit of pressure to where it creates a vacuum in the line and it will start jerking the pvb that just doesn't make sense to me, maybe the pump is to big.

I would think (could be wrong) that if I was going to pull from a 1" pipe to a booster pump, I'd be tempted to pump OUT to a 3/4" line. That would allow me to boost the pressure without needing a correpsonding increase in volume.

Just a thought.