Lorentz PSk3-7 Solar Borehole Pump and Controller

Lorentz PSk3-7 Solar Borehole Pump: Deep Lifts and Moderate Flows

The Lorentz PSk3-7 is the smaller of the two PSk3 solar submersible pumps, and the one to look at for deep water or a narrow borehole. Its C-SJ5-43 pump end lifts water 240 m through a 4 inch (100 mm) bore, the deepest lift in the PSk3 range, and the other pump ends cover moderate flows up to 128 m³/h. It is used for livestock watering, irrigation and farm or estate supplies where there is no mains power. The 8.3 kW controller drives a 4 or 5.5 kW three-phase motor, runs from solar panels with built-in MPPT, which keeps the pump working in poor light. It can also mix in grid or generator power if you want a back-up. The motor is a maintenance-free stainless steel unit with no electronics inside it. We supply the PSk3-7 in the UK as authorised Lorentz sales and service partners, and we size every system with Lorentz's own selection software.

A PSk3-7 system is made up of a controller, a motor and a pump end. The pump end is the part that moves the water, and it decides how much you get and how high it can be lifted. The eight centrifugal pump ends run from the C-SJ5-43, which lifts 240 m at up to 6.8 m³/h, to the C-SJ95-1, which moves 128 m³/h at a 16 m lift. Maximum head and maximum flow can't be had at the same time, because the flow falls as the lift goes up, so the right pump end depends on your borehole depth and the volume of water you need each day. If you need more flow than this, the larger PSk3-15 is built for it.

The PSk3-7 costs from £4,528.70 ex VAT, depending on the pump end.

Which PSk3-7 pump end do I need?

The eight pump ends cover heads from 16 m up to 240 m and flows from 6.8 to 128 m³/h. The C-SJ5-43 and C-SJ12-15 fit a borehole of 4 inches (100 mm) or more. The C-SJ8-30, C-SJ17-7, C-SJ17-9, C-SJ30-6 and C-SJ42-3 need at least 6 inches (150 mm), and the C-SJ95-1 needs at least 8 inches (200 mm).

Figures are the maximum for each pump end, from the current Lorentz datasheets (version 310270).

PSk3-7 controller and solar array

The controller handles up to 8.3 kW and accepts up to 850 V from the array, with a motor current of up to 13 A. It needs a maximum power voltage above 575 V, so the panels are wired in series strings. It is rated IP66 and works in ambient temperatures from -25 to 60 °C, and the pump can handle water up to 30 °C. The controller has analogue and digital sensor inputs, an integrated sun sensor, active temperature management and onboard data logging, and you set it up with the Lorentz Assistant app.

About 99% of the pump systems we supply run direct from the panels with no battery. The controller weighs 9.2 kg. The pump unit, which is the motor and pump end, weighs between 33 and 71 kg depending on the pump end. The size of the array depends on the pump end, the head and the volume of water you need each day.

What is included, and what you need to add

The PSk3-7 price covers the controller and the pump unit, which is the motor and your chosen pump end. You will also need solar panels and mounting, a rising main and a storage tank, and we can quote for the panels and mounting as well. Cable between the controller and the pump is supplied if you need it, and is quoted by length. Sensors are optional extras.

Pump sizing with Lorentz software

Sizing is free. We size every pump with Lorentz's own selection software, using the details you give us, and the result is an estimate of performance based on that data. It is not a guarantee of output. We supply the equipment, and the installation is carried out by you or your installer.

To size your pump we need the borehole depth and internal diameter, the water level, the height the water must be lifted to and how far it travels, and the volume of water you need each day. Send those details through our solar pump enquiry form. For more on choosing a pump, see our guide to solar borehole and well pumps.

PSk3-7 solar pump FAQs

How much water will a PSk3-7 deliver?

Up to 128 m³/h with the C-SJ95-1 at a 16 m lift, and 76 m³/h with the C-SJ42-3 at 30 m. For deep water the C-SJ5-43 delivers up to 6.8 m³/h at a 240 m lift. Output falls as the lift rises, and it is highest in summer because the pump runs directly from the panels. Our sizing gives you an estimate of the daily output for your site.

Will the PSk3-7 fit my borehole?

It needs a borehole of at least 4 inches (100 mm) for the C-SJ5-43 and C-SJ12-15, 6 inches (150 mm) for the C-SJ8-30, C-SJ17-7, C-SJ17-9, C-SJ30-6 and C-SJ42-3, or 8 inches (200 mm) for the C-SJ95-1.

Can the PSk3-7 pump at night?

Not on solar alone, because it runs from the sun. Most systems fill a tank during the day and supply from there when the sun is down. The PSk3-7 can also mix in grid or generator power if you need pumping outside daylight.

When should I choose the PSk3-7 rather than the PSk3-15?

Choose the PSk3-7 for deep lifts, up to 240 m, or where the borehole is only 4 inches. It also suits flows up to 128 m³/h at shallow lifts. If you need flows above that, or the larger 7.5 and 11 kW motors, look at the PSk3-15. For smaller duties, see the PS2-4000.