What does is mean when it says a water circulating pump has a max head of 10′?
Thanks
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WWPD
What does is mean when it says a water circulating pump has a max head of 10′?
Thanks
—————————————————————————–
WWPD
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Replies
I think it means the pump can rasie the water 10 feet
Pumps (and fans) are rated for flow and pressure, plotted on a curve to show you the performance of the pump at "all" values. At 0 gpm, the pump produces the most pressure, or maximum head, expressed in feet of water (2.31 ft h2o = 1 psi).
pumps can be derated for head
for example
10gph at 0'
5gph at 5'
1gph at 10'
don't know how it applies to circ pumps, just general info.
bobl Volo, non valeo
Baloney detecter WFR
Generally, a "max head of 10 ft" means that the circulator pump will develop 10 feet of water column pressure difference between the suction and discharge flanges MAXIMUM- at zero flow. This is referred to as the "dead head" pressure- the maximum differential pressure the pump will develop. The pump will have a curve showing the differential pressure (expressed in feet of head) that it will develop versus flow, known simply as a "head versus flow" curve.
Yup.
Ive seen stuff like 10 ft head @1 1/2 inch pipe / 500 gallons per hr .
12 ft head ,............................... 300 gph
so on
Sump pumps , the pump in the boat and shid like that tell it that way.
Tim
10' max head pressure is not much, but a 1' head pressure will still work on a closed system of a circulation pump.
If there was no air in the system, you can circulated water up 2 stories, its the water pressure that gets the water up 2 stories.
As others have said, 10 ft is the maximum differential head the pump can do. 10 ft head is approx 4 psi. Keep in mind, though, that it's differential head, the difference between the suction side and the discharge side. If you've got a closed loop with a circulator, the pump only has to overcome the friction it takes to push the water through the pipe.
That's correct. If the system is closed and full of water, it takes no differential pressure to get the water up two stories- because it's also coming DOWN two stories again as it returns to the pump suction. All the circulator pump does is overcome frictional losses in the lines, fittings, valves etc.- the elevation head is irrelevant.
That said, the pressure drop is proportional to the SQUARE of the flow- double the flow in a pipe and the pressure drop across that length of pipe increases fourfold. So doubling the pump differential pressure only increases the flow by about 40%. That's why it's so important to size your lines and valves correctly!
Remember also that if the pump has a maximum (dead-head) differential pressure of 10' of head, the flow at 10' head difference will be zero. In a closed system, what will happen is that the pump will 'ride the curve'- when you start the pump, the flow will increase until the head difference provided by the pump is equal to the total line losses at that flow. Whatever flow that is, that's all you get.
Sure, you can get by with 1' of head difference to circulate water- a couple feet of head difference is all that circulated the water in my ancient thermosiphon reboiler and radiators. The head difference arises in that case from the difference in density between hot and cold water- no pump needed. But that system is FAR from efficient! Lots of heat energy is wasted to provide that tiny head difference. And the lines required to give sufficient flow at those low heads are HUGE.
Thanks for all the info.
Not sure I have a full understanding of everything mentioned, but having some understanding of the new pump (Bell & Gossett NBF-12) is helpful.
this will be a closed loop system
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