can't get pump to work

Discussion in 'Irrigation' started by zliminator, Jun 27, 2006.

  1. zliminator

    zliminator LawnSite Member
    Posts: 82

    I'm replacing a well for a customer and redesigning their irrigation system. They originally had a 1HP pump and I'm using someone's 3/4HP well pump thinking it should be good for around 15 gpm, 30 feet. I measured the well with a string and weight before. The pipe in the well is 1 1/4" and it reduces down to 1" to the pump. I tested the pump in a 5 gal bucket of water and it works as long as its primed. I have a 1" check valve just before the inlet of the pump and don't think there are any air leaks. It doesn't work at all on the well. The only thing I can think of is that it looses its prime too fast or the pump is overrated as far as the specs. It was $99 from Harbor Freight Tools. It also has a tank. I'm stumped. Any ideas before I go buy a good 1 HP pump?

    Dan
     
  2. jerryrwm

    jerryrwm LawnSite Bronze Member
    Posts: 1,274

    Do you have a check valve at the bottom of the stand pipe? Makes it easier for that pump to draw water up if the pipe is already full.
     
  3. Wet_Boots

    Wet_Boots LawnSite Fanatic
    Posts: 47,992

    "30 feet?" is this the depth of the water level in the well shaft? Or the depth of the pump inlet pipe, for a well with a higher water level? You usually need to have a foot valve on the inlet pipe.

    Chuck the Harbor Freight pump. Use the real thing. Ninety-nine bucks buys you crapola.
     
  4. zliminator

    zliminator LawnSite Member
    Posts: 82

    I pulled up the pipe and there was a check valve at the bottom which was working. (I drilled holes in the pipe and water came out). The well is 30' deep and the other day the water level was 5' from the top. It was about 15' today. Anyway, I pulled up the 1 1/4" pipe and put in 1" with a new check valve. This time I only put it 20' down. It still didn't work even after I had primed the pump and filled the pipe with water. The only thing I can think of is that the pump just isn't strong enough. I'm going to buy a 1 HP Flotec at HD tonight.

    Dan
     
  5. Wet_Boots

    Wet_Boots LawnSite Fanatic
    Posts: 47,992

    Beyond 20 feet of drawdown, you lose efficiency and performance, and you need to look into a convertible jet pump, with two pipes (assuming this is a four-inch well shaft) going down to an injector assembly. Don't count on a home center pump to be the equivalent of one of the good cast-iron jet pumps. (and you do want a jet pump)

    Also, don't cheat on the inlet pipe size. That really can hurt performance. You want suction-line friction losses to be just about zero.
     
  6. zliminator

    zliminator LawnSite Member
    Posts: 82

    How do you convert a jet pump to work with a deep well?

    Why is a cast-iron pump better? Last longer? More powerful?

    Dan
     
  7. Wet_Boots

    Wet_Boots LawnSite Fanatic
    Posts: 47,992

    http://www.flintandwalling.com/converti.htm http://www.goulds.com/product.asp?ID=76&MASTERID=3 There isn't any rule requiring cast iron construction. But they are more durable than plastic. Sears sells plastic jet pumps, if you want to save a buck. Home Depot will have them, too. The 'pro' models have stronger motors (compare the 'service factor' ratings of cheapies to those of the real thing) - shallow well or deep well, a jet pump gives you more bang for your horsepower.
     
  8. speedbump

    speedbump LawnSite Member
    Posts: 117

    I fully agree, plastic pumps are junk.

    However they will lift water the same 25 feet that a good pump will if it is a shallow well jet pump. So you either have an air leak or your not holding your mouth right.

    The foot valve on the bottom is definately the way to go. Once the pipe and pump are full of water, all is primed and good to go. If it still won't pump, you have an air leak.

    If the well is 3" or bigger, you would do better with a submersible.

    bob...
     
  9. zliminator

    zliminator LawnSite Member
    Posts: 82

    I went by Polk Pump here in Lakeland, FL and got a Sta-rite SNE-L 1 HP. The guy said the ones at HD (Flotec) don't have replaceable parts like this one. Its also cast iron. The customer said she'd spring for the extra cost. I replaced the 1" pipe in the well with the original 1.25" but only went down 25'. I hooked up my "ninrocket" test manifold with several spray heads and it seemed to work for 5 seconds and then quit for 10. I added another 5' of pipe in the well and it worked fine as long as I didn't go to much over 15 gpm. I thought about adding a filter and flow switch. I talked to Dunham Well Digging in Winter Haven and he said don't bother, the maintenance isn't worth it. It already has a LP cutout switch. One problem I noticed is that it seemed to loose its prime for some reason. Especially when I would change one of the spray heads. I'm wondering if I need a check valve at the outlet.

    Dan
     
  10. zliminator

    zliminator LawnSite Member
    Posts: 82

    test manifold on discharge of 1 HP pump

    ninrocket.jpg
     

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