Little Giant PWM3900 Pond & Waterfall Pump – 3,240 GPH

The Little Giant PWM3900 Pond & Waterfall Pump is durable, reliable, and energy-efficient, using up to 60 % less electricity than direct drive pumps. The power and simplicity of operation with the Little Giant PWM3900 Wet Rotor Pump make it the perfect choice for many water gardening applications, especially waterfalls.

Key Features

• Nylon fiberglass construction
• Energy efficient
• Must be fully submerged
• No seals, no oil
• 20 ft.power cord
• Removable inline screen for “in-line” installation flexibility
• Removable 90° elbow included
• cULus listed

Warranty

• 1-year manufacturer’s limited warranty

IMPORTANT

• The Little Giant PWM3900 Pond & Waterfall Pump must be plugged in to a properly grounded and GFCI (Ground Fault Circuit Interrupter) protected 120 Volt outlet
• The Little Giant PWM3900 Pond & Waterfall Pump is not approved for use in swimming pools or salt water

Specifications

Little Giant Part Number	PWM3900 (517251)
Maximum Flow Rate	3,240 GPH
Flow Rate @ 1 Ft. of Head	3,240 GPH
Flow Rate @ 5 Ft. of Head	2,700 GPH
Flow Rate @ 10 Ft. of Head	1,380 GPH
Maximum Head	12.7 ft.
Power Consumption	280 W / 2.4 A
Discharge	1-1/2″ FPT (female threaded)
Fittings Included	1-1/2″ and 2″ adapters
Power Cord Length	20 ft.
Voltage	115 V, 60 Hz.
Dimensions	6-1/4″ Dia. x 11-1/2″ H

 

Pump Sizing

Continuous operation of these pumps in a pond or waterfall requires that the pump be sized for each specific installation. Pumps last longer and use less electricity when operated in the mid-range of their performance curve (see chart below). To calculate this, measure the height in feet from the surface of the pond water to the point where the water returns to the pond (perhaps a waterfall spillway). Add one (1) foot for every 90 degree elbow through which the water passes from the pump to the point of return. Add one (1) foot for every ten (10) foot length of tubing. This will provide the total height that the pump must move the water. Locate that height in feet on the vertical axis of the charts below and read to the right until you intersect the yellow/blue line. It is best to operate the pump in the head height shown by the blue area. If the lines intersect too far to the left of the graph you must choose a larger pump. If they intersect too far to the right you may either choose a smaller pump or install a ball valve at the discharge of the pump. By slightly closing the ball valve, never more than one third, you will create additional back-pressure on the pump that will allow it to operate correctly in the mid-range of its performance curve. Proper sizing of the pump to your specific installation will ensure optimal performance and maximum pump life.