Pump will not get to pressure

**KittyHandschuh** · 04-04-2011, 05:32 AM

Thank you for this forum!

I am having a battle with a Goulds pump which is now going into 3 weeks. I’ll try to explain the situation as best possible. This is on a small Caribbean island with not many resources for parts, pipes etc.
This pump supplies an entire household with water and is the ONLY supply of water for the house. It comes from a cistern. The system as described below has worked for over 25 years with pumps being replaced over the years. Always had been jet pumps.
The draw up pipe is 15 feet and then crosses over the cistern wall for two feet, then drops 9 feet to the pump. There is a valve at the top for priming. There is also a foot valve in the cistern. There is a check valve (one way flow valve) just before the inlet of the pump (I question if this is necessary). All piping to the pump is 1 ½ inch and the pump is 1.5 HP. It is an Irrigator but Goulds said this should work. Goulds said a jet pump is better but one was not available here.
The pump is new and was taken apart to make sure the impeller etc was not faulty.
The first problem is the pressure will not go above 38 psi. Second problem is the pressure cutoff switch will not shut off no matter how we adjust it. We have tried 4 switches and all the same problem. We have checked for air in the feed pipe and that seems not to be the case.
There is also a bladder tank set at about 18 psi. We have tried various settings on this also.

Any help would be greatly appreciated. Thanks Kitty

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**valveman** · 04-04-2011, 09:43 AM

That pump can only build 51 PSI total. With 15’ lift and a little friction loss, I figure 42 PSI max is all you can get. If your gauge is a couple pounds off, as most gauges are, 38 PSI doesn’t surprise me. A jet pump would have made much better pressure.

However, you should be able to loosen on the large adjustment screw in the pressure switch so it will shut off at 38 PSI. Of course that means you only have 18 PSI before the pump starts. I wouldn’t be happy with that. I would take the pump back to whoever told you it would work. Those pumps are made to produce 40 to 50 GPM at 20 to 30 PSI, but they were not meant to deliver much (enough) pressure.

If you can’t get a jet, a submersible would be even better.