pump head?

[mikoto]

I have been visiting these forums for a while, but have only posted a couple of times because I'm cutting my teeth here and find it easier to learn with my ears open than with my mouth open. That said, I need to clarify something very basic and important to me at this point.

I have recently had correspondence with someone who has expressed a different understanding of "head" than I have.

It is my understanding that to say a 200GPH pump has a 4' head means that it will push an unspecified (perhaps implied by the ID of its outlet) volume of water 4' vertically before sufficient back pressure has accrued to force the stoppage of flow, and only push 200GPH with a theoretical zero restriction on flow. Am I correct?

To my understanding if the same pump in question could push 200gph @ 4', its maximum head would be somewhat greater than 4'.

Thanks

[bigben2k]

That's correct.

It's easy to get it confused, because we often present pumps as "ModelX, yyy gph, zzz head", where yyy is the max flow rate at no head, and zzz is the max head, aka dead head, where the flow rate drops to zero. But if we specifically state 200 gph @ 4 feet, then the max head (aka dead head) is indeed higher.