Solar Slowpump
©2003 Windy Dankoff

Slowpump can push water as high as 450 vertical feet (137m) and use solar-electric power to provide 200 to 2,600 gallons per day (750 to 10,000 liters) from shallow water sources.
Solar Slowpump was the world's first commercially available low power solar pump. It was developed by Windy Dankoff in 1983, in response to those who said "that's impossible". Thousands of Slowpumps have been installed worldwide by ranchers, homeowners, missionaries, health workers, government agencies, etc. Some of our oldest Slowpumps are still in daily service.
Slowpump draws water from shallow wells, springs, cisterns, tanks, ponds, rivers, and streams, and push it as high as 450 vertical feet and through miles (kilometers) of pipeline. Slow pumping minimizes the size and cost of the solar array, wire and piping. Slowpump is less expensive than submersible DC pumps, and made in a much wider range of sizes. Wearing parts typically last 5 to 10 years. Overall life expectancy is 15 to 20 years. Slowpumps are not submersible.
"These pumps work great....Even during low light levels when the motor is turning slowly, a small amount of water can be pumped....The manual is easy to read. Windy's troubleshooting section is excellent....Not only have these pumps stood the test of time, but small changes have made them even better."
B. Schultze
product review in Home Power Magazine No.42
"Over the last five years, we've found the Slowpump to perform impressively. We've also been very happy with Dankoff [Conergy]'s friendly service and great attitude."
JT, Nemia Valley, BC, Canada

Rotary vane mechanism (positive displacement) made of forged brass, carbon-graphite and stainless steel
NSF® approved for drinking water
Handles sea water, dissolved minerals
Survives most freezes
Permanent magnet, DC motor
AC models use a low-surge PM motor that greatly reduces starting surges, inverter and wire size requirements
Installation and Service Manual is highly detailed and illustrated

20 vertical feet (6 m) at sea level. subtract 1 ft. for every 1000 ft. altitude (1 m for every 1000 m). Pump should be placed as low as possible.

This pump CANNOT tolerate dirt. Water MUST be filtered clear. If water is very dirty, improve the source or consider a different pump.

The rated power of the PV array must exceed pump watts by 20% or more.

A Linear Current Booster (controller) is required to start and run in low light

Solar Tracker (optional) will increase daily yield (40-55% in summer)

No.20242 Intake Strainer/Foot Valve: Monel metal screen, stops coarse debris
No.20235 Inline Filter: (10inch) Uses standard filter cartridges
No.20237 Intake Filter/Foot Valve: (30inch) Replaces Intake Strainer and Inline Filter with a single unit, may be lowered into a shallow well or stream
Spare Filter Cartridges: (5 or 10 micron spun fiber)
- No.20236 10inch 2 pack
- No.20238 30inch 3 pack
Dry Run Switch: Prevents pump damage if source runs dry No.20240 for 1300/1400 Series No.20241 for 2500/2600 Series
No.20308 Close Elbows for use in 6 to 10inch (150-250 cm) well casings
Linear Current Booster (LCB) required for PV-Direct: Specify voltage and current (amps = watts from performance chart divided by volts)
Fittings:
- 1300/1400 Series: 1/2inch female
- 2500/2600 Series: 3/4inch male

1 year against defects in materials and workmanship