reedman
Well-known member
For a crawlspace I'd go for one of the Iwakis. The are rock solid and can deal with the back pressure. They are a little noisy, but in your case (the crawl space) it doesn't really matter.
Slickdonkey said:Maybe this would be worth posting in a new thread, but if I use my Hammerhead for the CL pump, can anyone suggest a return pump and/or utility pump?
The sump is going to be in the crawlspace, so there is about 12ft of vertical head, plus maybe another 8ft of head loss from plumbing (per RC calculators). If I'm looking for a flow of say 1500-1800gph through the sump, what's the most efficient pump to do this with?
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NeuroDoc said:Is that 12ft calculated head or actual distance? It was my understanding that the assistance given to the pump from gravity (on return) reduces the head by ~50%.
Scooterman said:Use the calculators to figure out your total head loss, these should help you determine what size pump you will need, take your time and do it right because it could make a big difference.
To build a closed loop system means that water is gravity fed to a Pump through BULKHEADS in the DISPLAY TANK and then RETURNED through BULKHEADS and/or plumbing that is placed IN THE DISPLAY TANK BELOW THE WATER LINE ;
The way this works is quite simple. There is no Head Pressure. That is, Since both intake and output is in the main tank with the same water level the static head is ZERO.
Static Head is the pressure that the Pump has to PUSH AGAINST from the start. That is, with the pump turned OFF the pressure of the water that remains in the return line.
Static Pressure =0
(NOTE: this is not the head pressure caused by friction of pipe walls or bends and/or connectors like elbows etc)
In a CLOSED LOOP SYSTEM the pressure of the water in the main tank is pushing the water through the Bulkheads or "drains" to the inlet of the pump and the return line is also below the surface producing Zero Head Pressure creating a CLOSED LOOP. The pump doesn't have to work as hard and reaches its maximum flow minus elbow or wall friction.
It doesn't matter where your intake or outputs are as long as they are below the display water surface. And it doesn't matter where your closed loop pump is or how far the inlet and outlet destinations are.
The only factor that reduces flow is remaining friction loss, which can be as much or more than static head if you don't plan your plumbing carefully.
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