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pump losing water pressure

Posted by dbeaty2 FL (My Page) on
Sun, Jun 4, 06 at 17:31

I inherited an irrigation system at my home that works, but every few minutes, the sprinkler heads lose pressure and stop, then they start up again after spurting air a bit.

I have a 1 1/2 hp cent. pump with shallow well and I uncovered the suction lines to the well head to check for leaks. Nothing obvious. I can hear the pump when it loses water as the pitch increases, the heads stop spraying.

Could it be a bad check valve? There's a brass one on the 2 inch suction line. Or something else I could try?



Follow-Up Postings:

RE: pump losing water pressure

doesn't the check valve prevent water from flowing back into the well when the pumps off? sounds like you problem is air getting into the line prior to the pump (It's not getting in after the pump).

RE: pump losing water pressure

I have the same problem and would like to know how to troubleshoot this problem (ping point the leak). Any tips you can provide would be greatly appreciated.

RE: pump losing water pressure

  • Posted by mikie z9 St.Pete.FL (My Page) on
    Fri, Jun 9, 06 at 0:27

Sounds like the check valve is working as you dont mention loosing prime or pumping huge amounts of air. So it sounds like the pipes are full of water up to the check.

So maybe concentrate mostly looking for leakes from the check to the pump. Loose or cracked intake fitting ?

Pump has a couple of shaft seals too that if leaking could cause cavitation and wet on the electric side could ruin the motor.

Maybe its just full of sand and once pressured up that grit is causing cavitation, so it quits pumping and acts like you describe. Usually a plug toward the bottom of the empellor body, remove it and power the pump on, or just hook some city water to another point to flush it out. Probably see a small slurry of sand come out when you remove the drain plug.

Maybe soapy water in a squirt bottle.
Try different things like, Bring it up to pressure and turn it off.

You say you inherited... has it always done this ? Perhaps that would indicate not enough well points and bubbles are comeing up filling some low spot in piping until they release and suddenly the impellor isnt sucking water till that air is expelled . 1.5 hp centrifical pump needs 6 - 1.25x4' points around here usually.

I dunno... just things to think about and look for.

RE: pump losing water pressure

You're either sucking air (re-pipe the suction side of the well including replacing the check valve; use as few threaded connections as possible, put pipe dope NOT TAPE on any you do have) or your well is drying up.

You can try treating the well - go to your local irrigation supply and ask for a product called Welltone (there are other equivalents on the market). Follow the instructions, repipe the suction side and wait as long as you can stand it before turning the pump on - 2-3 days minimum.

If none of that does the trick, it's time for a new well.

RE: pump losing water pressure

Turn off the pump and let it sit for a couple of hours. Then check for very small amounts of water on the suction side. A very tiny water leak will create a very significant air leak when the pump is running. Leaks like this can be fixed with a good quality epoxy such as JB Weld.

RE: pump losing water pressure

I just put in a new pump and had a new sand point put in. What's happening is that the sprinklers will come on, run for a little but, then lose all pressure, takes a few minutes then comes back on. This goes on in the backyard only, but all front zones are working but they only have 3 heads to a zone, instead of 4. Could this be something wrong with the sand point?

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