Floating Pumps

Floating Pumps - Grundfos / Lorentz

Pumping Water from Dams, Ponds, Lakes or Lagoons

Floating pumps are semi-submersible pumps held in place and protected by a floating device. Designed for situation where an inline pump is not suitable. Floating pumps are commonly used on dams, lakes or lagoons. Our semi-submersible pumps can deliver up to 7,000 litres per hour.

Alternatively, a fully submersible bore pump can also be floated when attached to an appropriate device.

The cost of the pump system is directly proportional to the required litres per day and the vertical lift (also known as head). A single solar panel can lift water up to 20 metres.

Below are two solar powered floating pump systems designed for Northern NSW. Many other configurations are possible (and available). The selection of the most appropriate pump should be based on the actual requirements (location, volume and pressure/head). Pump systems are supplied as DIY install kits only.

Floating Pump System Guide
litres/day @ vertical lift Solar Pump System Price
21,000 @ 5 m or 7,100 @  15 m Lorentz PS150 Boost with 0.26kW PV from $3599
25,000 @ 20 m or 17,500 @  60 m Grundfos CRFlex 3-11 with 1.56kW PV from $7199

Floating Pump System Examples

Lorentz PU150 - Submersible Pump

Lorentz PS150 Centrifugal Rotor pump

Lorentz PS150 centrifugal rotor pumps are submersible pumps for low to medium heads and high flows. They can be powered by a single 24V solar panel. The Lorentz float holds the pump in place (horizontally).

The below system configuration will pump water up to 20m, delivering about 1,000 litres per hour (of full sunshine) or 4,500L/day. View Graph.

Lorentz PS150 solar pump system

Trina 210W Solar Panel
Trina Solar

210W Solar Panel

Lorentz PU150 C-SJ5-8 submersible pump

Submersible bore pump

Lorentz PS150 pump Controller

Pump Controller

  • 1 x 210W Trina Quadmax solar panel
  • 1 x Lorentz PU150 C-SJ5-8 submersible pump
  • 1 x Lorentz PS150 Pump Controller
  • 1 x Lorentz Pump Float
  • 2 m solar cable and MC4 connectors
  • 10 m underwater bore cable
  • DC Breaker (IP66)
  • Potting of underwater cable
  • Installation & operation manuals

Price: from $3599

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Grundfos MTR Flex – Floating Pump

Grundfos MTR Flex Family

The Grundfos MTR Flex semi-submersible Pump can be solar powered (DC power supply) or mains powered (230V AC power). The bottom half of the pump is immersed in water while the other half (the motor) remains above the surface.

The below system configuration will pump water up to 90m, delivering over 3000 litres per hour (of full sunshine). View Graph.

Grundfos MTRFlex solar pump system

Trina 260W Solar Panel
Trina Solar

6 x 260W Solar Panels

Grundfos MTR Centrifugal Rotor Pump End
Grundfos MTR

Centrifugal rotor pump

Grundfos MG Flex Motor
Grundfos MG Flex

Intelligent Motor

Grundfos Pontoon
Grundfos Pontoon

Floating Pump Island

  • 6 x 260W Trina Honey Module® solar panel
  • Grundfos MTRFlex 3-11 semi-immersible pump system
  • Grundfos Pontoon Float
  • 2 m solar cable and MC4 connectors
  • 10 m motor cable
  • DC breaker (IP66)
  • Earth stake
  • Installation & operation manuals

Price: from $7199

Get A Quote


Both Lorentz and Grundfos pumps are driven by DC brushless motors running at varying speeds depending upon the energy input available. Both pumps are designed for operation with PV solar modules and utilise MPPT technology to optimise performance. Both systems allow for optional connection of high and/or low level sensors. There are a few differences:


  • Requires pump controller
  • Can run off 12 or 24V batteries
  • Over-temperature and overload protection
  • Requires waterproof cable connection


  • All controls are in the pump
  • Can run off 230V AC (generator or grid)
  • Under/over-voltage and overload protection
  • Requires stormproof pontoon

For automated cut-off (e.g. when header tank is full) a float switch is required, or alternatively a float valve in combination with a pressure sensor.


Grundfos MTRFlex Family

  • Stock Watering - large rebates available
  • Small-scale irrigation
  • Agricultural water supply and transfer
  • Emergency reserve water supply
  • Bushfire prevention
  • Dewatering of quarries and open pit excavations
  • Water supply for dust control


Solar pump systems are easy to install and instructions are provided. However, floating pumps require special protection from rain (Grundfos only), falling branches, currents or storm. Also, pumps floating in murky waters may need a filtering system to prevent grid and debris getting into the pump.

Home made floating devices

Of course you can make your own floating device to hold the pump. However, we strongly advise you go the extra length and get the floaters designed for these pumps. Rickety pontoons or platforms may fall apart during a storm, possibly sinking the pump to the ground. The savings may not be worth the risk.

You could also employ an Off-Grid accredited installer and claim STCs. For example, the 6 Panel Grundfos Kit would currently create $1216 worth of STCs. You may also qualify for other rebates.

Should you ever get stuck during installation or thereafter, phone and/or email support is available at no extra cost. Note: Rainbow Power Company does not install pump systems.

Trusted Brands

Lorentz logo

LORENTZ is a market leader in solar powered water pumping solutions. Products are built tough for operation in "hostile" environments and simple to service.

Grundfos logo

Grundfos' speciality is the design and development of energy-efficient solutions and many of their products are ideally suited for use with a stand alone solar system.

We install solar systems in Northern NSW and Southern QLD.

Gold Coast (from Coolangatta to Southport), Nerang and Hinterland (Beaudesert) and out West (Warwick, Stanthorpe, Killarney)

Northern NSW (Tweed Heads to Yamba, including Evans Head, Byron Bay and Ballina); the Far North Coast Hinterland (Grafton via Lismore to Murwillumbah) and out West (Casino to Tenterfield, including Drake and Tabulam, as well as Woodenbong and Bonalbo)

For larger system we also go up to Brisbane or down to Coffs Harbour and even Glen Innes. Other places by arrangement.