# Question on jet pumps and irrigation system capacity



## turbopenguin (Aug 11, 2020)

Hello!
I'm very new to lawncare/irrigation systems and am getting new sod installed next week (CitraBlue St. Augustine). Before it gets installed, I want to make sure my sprinkler system is optimized. We moved into our house about 5 years ago and it came with an irrigation system in place, but literally every sprinkler is a different brand or model.

Our house is on a canal in South Florida. There's a 1.5 hp pump, but I have no idea where it is pumping the water from. Some people say there's probably a well, others say it pumps from the canal. I don't see any pipes coming out of the seawall, though.

My goal here is to get matching precipitation rates with head to head coverage, but I don't know anything about the pump other than the horsepower.


We have about 1700 sq. ft. of lawn (dirt at the moment) in the front, nothing in the backyard. The system currently works and gets all the sprinklers to run -- 5 rotors and 5 sprays, but not head to head coverage.


I screwed a pressure gauge onto the spigot above the pump and opened up and got a 40 PSI reading. Is that accurate?


closeup of motor label


I don't understand what the box on the left is for. The box on the right is the timer and on/off/auto switch.


Left box.

Is it safe to add sprinkler heads or is the system already at capacity? What information do I need to even determine that?

Any help is greatly appreciated!


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## TSGarp007 (May 22, 2018)

Lots of information here. You don't have much time. You could do the 'wet test' to determine your gpm at your 'design pressure.'

You could open the box on the left, but I am assuming that is your electrical power. Your power goes from there to the intermatic timer, and that timer transfers that electrical power to the pump based on your timer settings, or you can override it with the manual on/off switch. I had an old pool once and that was exactly how it was setup.

How many sprinklers do you want to add? Have you come up with a design? You'll need to map out the property and figure out where you have sprinklers, and where you want them, figuring out the radius and gpm of each nozzle. I'm assuming in this case you will keep the existing heads in place? If you do the wet test and figure out your gpm, and you figure out how much gpm you need from your design, then you'll have an idea if the pump can handle that output.

If it can't handle the output, all is not lost, you just add another zone. But that means any sprinklers added will need to have a separate piping system back to the pump area. You could just do that now, and decide later whether to tap into the same existing zone or create a new zone. You will need a new timer, in this case an actual irrigation controller. And I guess some kind of relay to get the timer to control the pump (replacing the intermatic). I think if a possible new zone doesn't use enough gpm, then maybe something called a constant pressure valve or something like that would help protect the pump. Or you could change up your pump system to have the pump controlled by a pressure switch in a water pressure tank. Any time the water pressure drops too low, the pump kicks on, any time the pressure in the tank gets too high, the tank cuts off. Then the irrigation controller simply opens the irrigation valves (which I guess you currently don't have any of, but they are cheap), and once the water starts flowing, the pressure in the water pressure tanks starts to drop, and the pump will automatically kick in when it needs to.

Anyways, this info isn't presented very well, sorry. And I know there are people on this forum that probably have a setup like yours, and definitely a lot that have a well with an irrigation system, and they may chime in with more/better info. BUT, I do recommend putting those sprinklers in where you want them very soon. If you run the pipe for the new sprinklers all the way back to the pump, you can figure out the rest later (you could tap into existing piping or create a new zone). No one wants to dig in brand new sod...

Oh, maybe do a permit search on your property with your county. The well probably has to be permitted, and maybe it was. Or maybe it's so shallow someone just did it real quick and there is no record of it. I wouldn't tell the permit office about it, just check to see if it was permitted online (so you don't have to deal with any red tape). If it was permitted, maybe it has a well record that says what the well generated when it was installed, it would have a chart of gallons per minute after so many minutes of pumping, how deep the well is, etc. That being said an actual test is probably still a really good idea.


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