Irrigation pump pulsating Cancel The title field is required!

1. Michael Wagner

   

   0 posts
   
   4/22/2016 8:04 AM

   I have an 8 inch draft pipe that goes into a river about 15 feet below my pump and the issue I'm having is when it gets up to pressure the water seems to pulsate like it is pumping then not over and over and is sounds like there might be air getting into the pump. The pump is not slowing down or anything like that. This is not a VFD it is direct drive with 2 pressure release valves on the system to keep the pressure around 110 psi. I'm wondering if My draft pipe could have a hole or something where it is sucking air or if there could be another issue that I'm unaware of. Any thoughts are welcome.

   
   
   
   
2. Keith Fellenstein

   

   0 posts
   
   4/22/2016 10:04 AM

   Couple things off top of my head. Seems pumps can't keep up with demand and are cavitating. Is it possible the intake is partially blocked restricting flow? Has the water level in your source dropped and pumps don't have enough suction? Have you tried reducing flow on the outgoing main to diagnose and as temporary fix until source is determined? Has one of the pressure relief valves failed and is continuously dumping?

   
   
   
   
3. Peter Bowman

   

   11 posts
   
   4/22/2016 10:04 AM

   Michel,
   
   Sounds like what happened recently with my domestic well at home. I Google-searched the symptoms and it came up "short cycling." http://inspectapedia.com/water/Water_Pu ... _Table.php
   
   So I called my local pump guy, and as a temporary fix he suggested draining the system, then unscrewing the pressure guage to allow more air into the system, then re-filling system. It worked for awhile, but back to the same symptoms now.
   
   I probably need to get him out here, since it likely won't look good on my power bill this month.

   
   
   
   
4. Michael Wagner

   

   0 posts
   
   4/22/2016 1:04 PM

   Keith Fellenstein said: Couple things off top of my head. Seems pumps can't keep up with demand and are cavitating. Is it possible the intake is partially blocked restricting flow? Has the water level in your source dropped and pumps don't have enough suction? Have you tried reducing flow on the outgoing main to diagnose and as temporary fix until source is determined? Has one of the pressure relief valves failed and is continuously dumping?

   
   I think you might be right about the cavitating. It seems very strange to me that this is suddenly an issue though. I did have my pump replaced last fall but never had the opportunity to use it after it was replaced. The replacement is literally identical to the one it replaced though and there was no cavitating before. The intake is completely clear and both pressure relief valves appear to be working correctly. The pump will pump at it's 900 GPM capacity but still pulses and I'm wondering if the new pump is just too efficient for the pipe design. I guess I don't know where to go from here.

   
   
   
   
5. Clay Putnam

   

   33 posts
   
   4/24/2016 6:04 PM

   The first call I would make is to the company that replaced the pump.

   
   
   
   
6. Andy Jorgensen

   

   1 posts
   
   4/25/2016 6:04 AM

   Clay Putnam, CGCS said: The first call I would make is to the company that replaced the pump.

   
   
   
   Ditto.
   
   But sounds like it is sucking air.

   
   
   
   
7. Kenneth Ingram

   

   18 posts
   
   4/25/2016 6:04 AM

   I remember one of the drought years back in the 2000's. Lake level was very low. You could see a vortex (tornado like funnel) out in the lake at the end of the intake but there was still several inches of water above. Out on the course you could see sprinklers lose pressure, then regain pressure, over and over again. Seems like you are sucking air. Good luck. Very dry here in Maryland. Kenneth Ingram, UMD.

   
   
   
   
8. Clay Putnam

   

   33 posts
   
   4/25/2016 9:04 AM

   Andy Jorgensen said:

   Clay Putnam, CGCS said: The first call I would make is to the company that replaced the pump.

   
   
   
   Ditto.
   
   But sounds like it is sucking air.

   
   
   I would still make the call.

   
   
   
   
9. Michael Wagner

   

   0 posts
   
   4/27/2016 11:04 AM

   I have called the company that supplied the pump and after some investigating it would appear the old pump had an inducer added to it that we were unaware of and the new pump didn't come with one. Should be as simple as unscrewing the impeller bolt and adding an inducer. Thanks for the help!

   
   
   
   
10. James Smith

    

    112 posts
    
    5/24/2016 6:05 AM

    Another thing I would say to check out is the back flow preventor between your pump and the tank/clay valve. I had my Jockey pump back flow preventor that had rusted up inside and stopped closing down all the way. as soon as the pumps would shut off the water flowed back into our wet well and the pump would kick on again.