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wet rotor pumps in series
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Plumdog_2
Member Posts: 873
four pumps, two in series above two more in series, and the two pairs are parallel piped. I saw it and I thought "why"? Why not just get one proper pump and quit screwing around?
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Wet Rotor pumps in series
When "stacking" wet rotor pumps in series, it is my recollection that you increase the GPM pumping through the system. Is that correct?0 
I don't think...
so..You increace Head...GPM is if you do them in parallel....kpc
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Kevin is correct
Series mounting increases head (pressure) at about the same flow. Parallel increases flow at a common pressure. Not the same pressure as one running but a common pressure where they both settle in equilibrium.
EDIT: As noted below, each follows their curve but stacking the circulators is no way to double your flow if that is your goal. In the end, if you need that much head, I think you have too much pressure drop."If you do not know the answer, say, "I do not know the answer", and you will be correct!"
Ernie White, my Dad0 
That's always looked so cool to me. I think when I finally convert my new house from warm air to hot water I'm going to buy some of the tiniest tiniest circulators I can find and stack them,.. just because I CAN!
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0 
flow and head
It depends on whether you have an existing system or you get to design the system the series pumps are connected to.
If you have an existing system, you are stuck with that system curve. You can only shift the operating point along that system curve.
If it is a new system and you get to control the system curve, you can make anything happen.0 
Come on guys...
Same flow at an increased head? If you put 2 pumps in series the flow will be increased. The combination will have a curve more like a larger higher head pump, but the flow will not stay the same.0 
Page 190192 of "Modern Hydronic Heating" by John Siegenthaler
It uses an example of two 7.6 gpm circs producing 10.5 gpm in series at double the head.
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0 
What happens when
you pipe them in parallel and wire them in series?0 
You are right Uni
Not exactly the same flow but not doubled. Each does follow their curve and each curve is different. Thanks for checking in."If you do not know the answer, say, "I do not know the answer", and you will be correct!"
Ernie White, my Dad0 
Um...
... Less. ;~)0 
then
you are doubling the flow at half voltage due to double voltage drops, decreasing the rotor speed at a ratio inversly proportional to the electrical resistance of each winding to a factor of 1/x where x= the inrushing current not allowing for the slight shift in phase.
honestly don't know.
if you cant dazzle em with brilliance..baffle em with....
mitch0 
and the objective
of the exercise is to match the pump(s) to the system, so that the pump(s) are operating at their best efficiency. The key to adding the things up is that if you pipe them in parallel, both pumps will operate at the same total dynamic head, and the flows from the two pumps (which will be the same, if the pumps are identical) will add. If you pipe them in series, the flow in the two pumps will be the same, and the total dynamic heads will add.
In either case the system will operate at the point where the combined pump curve crosses the system flow/head curve; you will likely have to draw them both on the same graph to find out where that will be (I always do...).Br. Jamie, osb
Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England0 
with the flow check
open you get heat, flowchecks closed you get cold.0
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