Help pumping water from a pond.

[MEM1]

First I must let everyone know I am an idiot when it comes to pumps and pumping systems. So please bare with me if I get really confused. Here's my problem:

I am trying to pump water out of a pond. My pump sits on the berm of the pond and is driven by a gas powered engine. The suction line of my pump is 15 inches in diameter, and the inlet of the suction line is 18 feet lower than the pump. I need to know if my pump will pull water out of the pond sitting 18 feet above the inlet of the suction line. What information and formula do I need to calculate the answer, or is there an easier way? Any help is greatly appreciated.

By the way, I posted this question in one of the other forums before I found this forum, so I apologize if anyone see and replies to both.

 

[MortenA]

It should be possible but you need to check the NPSHr for your pump. If its higher than 12-14 ft you may have a problem.

Your pump should also be "self-priming". Maybe a submerged pump would be better?

Best Regards

Morten

 

[d23]

MEM1

Is the inlet of the pump 18 feet from the pump or from the water level? Pump to water level is the big consideration, but not the only one.

To expand on Morten's post centrifugal pumps do not suck. They operate based on intake pressure. The pump manufacture can provide a NPSHr curve that will tell you if the pump will work in your application. Being above the water level a "self-priming" function may be required to prevent cavitation or manual priming.

If you cannot find a curve you may want to let everyone know what the pump is. Aditional information may be available from this post.

 

[Kawartha]

MEM1,

Above comments do apply to your case.

1)What you have to consider is the actual lift required (the distance from the water level in the pond to the centerline of the impeller),

2)You have not advised the type of pump that you are using. Is it a centrifugal? Is it a self-priming centrifugal? If it is not a self priming centrifugal or a positive displacement type pump, it will not prime. In other words, it will not pump.

3)You indicated that the suction line is 15" diameter (pipe or hose?). Does the pump require such a large intake pipe? Even a self-priming pump will work forever trying to push the air out of the suction pipe into the discharge pipe. You may have so much air to move, that even with a self priming pump the circulating liquid will heat up and possibly cause problems.

4)Another way to prime the pump is to install a foot valve at the end of the suction line, then hand fill the entire suction line to above the pump elevation. Once you have primed the system the foot valve will keep the pump primed for future starts. This of course will only be true if the foot valve holds (this is always a problem with foot valves).

5)If you have a self priming pump, you must allow the air being moved through the pump to discharge from the discharge pipe with little or no back pressure. For example, if you have a discharge check valve with a head of liquid above the valve, it will take forever to fill the pump suction with liquid.

MEM1 - You may want to provide some feedback, so that further comments can be provided.