DC Pressurizing Pumps for Domestic Water Supply and Irrigation

©2003 Windy Dankoff

Why Pressurize? A water tank must be elevated100 vertical feet to produce modest house pressure of 40 PSI. It is far more practical to install a pressurizing pump with a small pressure tank. This is the way conventional home water wells work, so the technique is perfectly ordinary. . . unless you are generating your own power using battery storage. If so, you should pay critical attention to your choice of pump.

Why use DC? -- when we can get a high quality inverter, and a low cost AC pump?

• Efficiency: Conergy DC pumps use one third to one half the energy of conventional AC pumps, and eliminate high starting surges.
• Quality: Compared to plastic RV/Marine pumps often used in DC systems, high quality solar pumps are more powerful, quieter, and last 5 to 10 times as long.
• Reliability: Inverters can fail, requiring factory repair. With a DC pump, you will not be out of water.

Testimonial: "I was hauling both washing water and drinking water for over ten years. Now with this pump and a very minimal solar system, I have this wonderful thing they call faucets, and out magically comes the water!"
Ms. C.S., Chimayo, NM USA, owner of Flowlight Booster Pump by [Dankoff] Conergy

We do AC too !

AC pumping is best for some situations, particularly where wiring distances are greater than 200 feet, or where it is difficult to replace AC wire with larger DC wire. For these applications, Conergy offers AC versions of both Flowlight Booster and Solar Force pumps. You can buy an ordinary AC jet pump for less than half the price, so why use Conergy pumps?

Efficiency: Again, Conergy pumps use 1/3 to 1/2 the energy. Buying an efficient pump is much cheaper than enlarging a power system. Low Surge: Ordinary AC pumps use induction motors, which require 5 to 10 times their running current to start. Conergy AC pumps use "rectified DC motors", which start without a high surge. This places far less demand on inverter capacity, and greatly reduces wire size requirements. They will not burn out from excessive voltage drop.

General Rules for Installing a Surface Pump

Pumps are better at pushing water than sucking it. Excessive suction causes cavitation. This is when vapor bubbles form, and then implode inside the pump. This produces loud noise and excessive pump wear. To avoid problems: Locate the pump close to the water source.

• Place the pump below the water source (tank) if feasible. If not, minimize the vertical distance (suction lift) from the source to the pump.
• Minimize friction by using intake pipe of 1 to 2-inch size. (Outlet pipe may be smaller.)
• Avoid creating high-points in the intake pipe. They can trap air pockets that restrict flow. If one is unavoidable, install a Tee with a cap, to allow full priming (displacing air with water). An automatic air-vent valve may be indicated

Call your dealer or the factory if you have questions during planning or installation.