Question
Hello, Been having issues with coverage with my sprinkler system, some of the heads didn't have good pressure so when my old pump died a 1.5 Sta-Rite, I replaced it with a 2 horse Sta-Rite thinking I would get better coverage with more power.  Now it appears things are worse. Instead of a strong spray, I get a pulsating spray and the coverage is worse. I've spoken to my pump provider, and they said I need to check the gpm from the well. They also suggested that my screen on the well tip is clogged, but I don't have a screen, my well driller gave me an "open ended well, meaning he pounded the well head down deep into coral and I draw my water through the coral, not a screen.  Anyway, I am at my wits end with this. Do you have any suggestions?  Thanks for your insight.

Answer
Hi Craig

This case seems a little strange considering a 2 HP pump should give you better flow rates.  You don't mention in your e-mail whether the well and pump are exclusively used for irrigation.  Since you make no mention of a pressure tank, I'll assume the well and pump are for irrigation only.  

The first thing you should check is line voltage - most Berkeley & Sta-rite 2 HP pumps require 230v to operate where a 1 1/2 HP only requires 110v.

You should troubleshoot the source of water and the pump in order to isolate the issue.  If it's possible, disconnect the irrigation main line from the pump and run a supplementary line from the pump discharge to ensure the pump is drawing water properly.  If you cannot disconnect the irrigation pipe easily, then open the turf  valve (or hose bib) installed in the main line to winterize the system. If it flows freely without pulsing, then you know you probably have an issue with the irrigation main line somewhere downstream of the blow-out provision and the pump is fine. If this is the case, don't waste time and money trying to find the source of the pipe restriction, simply abandon the existing main and have a new one installed.

As your pump provider suggested, consider having a well flow test to ensure the irrigation system is not putting too large a demand on a well that possibly has a lower refresh rate than the irrigation system's demand.  If the well can't keep up, you'll make it really hard on the new pump you recently purchased and the system's performance will always be lacking.

If you do have a pressure tank, and the well supplies your house as well as your irrigation system, your pressure tank may be water-logged.  When a pressure tank is installed in a well system, air is injected into the tank to provide the necessary pressure to move the water through the plumbing.  From time to time, this air pocket leaks out causing reduced pressure and flow from the tank.

Hope this helps - Good Luck!

Tony