Pentax CR Centrifugal Soft Solids Handling Pumps

Where to Use Pentax CR Pumps

The CR is at home on farms, smallholdings, nurseries and large gardens. Typical jobs include irrigating from a reservoir, pond or ditch, filling and emptying tanks and troughs, and feeding wash-down points where the water carries some silt or plant debris. Because the open impeller tolerates soft solids, it copes with surface water that would quickly clog a clean water pump.

Site the pump on a firm, dry base, under cover and as close to the water as you can. Keep the suction pipe short, airtight and at least the full 1½” bore, and avoid unnecessary bends, because every extra metre of lift on the suction side reduces what the pump can deliver. Our guide to suction lift and NPSH explains the limits, and the guide to pump head and flow rate shows how to work out the head your system needs.

The CR is not the answer to every job. It is not self-priming, so if the pump has to sit well above the water and pull it up, a self-priming pump is usually easier to live with. For clean water at higher pressure, look at the Pentax CM range.

Frequently Asked Questions

What does “soft solids up to 10 mm” mean?

Pentax states that the open impeller passes small solids up to 10 mm in diameter. That covers silt, fine grit, leaves and similar soft debris carried in surface water. It does not cover stones, rag, fibrous material or sewage, so fit a strainer or foot valve with a strainer on the suction line.

Is the Pentax CR self-priming?

No. The CR is a standard centrifugal pump, so the pump casing and suction pipe must be full of water before it starts. Either install it below the water level so the water flows in on its own, or fit a foot valve at the end of the suction pipe and fill the line through the priming plug. Our guide on how to prime a pump walks through it. Never run the pump dry, as that damages the mechanical seal.

What is the difference between the CR100 and the CRT100?

Only the motor. The CR100 runs on 230v single-phase and draws 5.3 A; the CRT100 runs on 400v three-phase and draws 2.4 A. Both use the same 0.74 kW rating and pump end, so flow and head are identical. Use the CRT100 where a three-phase supply is available, and wire it through a starter with suitable overload protection.

Can the CR pump hot water?

The limit depends on the impeller. Pentax rates the CR at up to 90 °C with a brass impeller and up to 50 °C with a Noryl impeller, with a maximum operating pressure of 6 bar. If you need to pump warm water, call us to confirm which impeller is fitted before you order.

Can the pump be left outdoors?

The motor is rated IPX4 by Pentax, which means it is protected against splashing water but not against flooding or being hosed down. Mount it under cover or in a ventilated pump house, raised clear of the floor, and never submerge it.

If you would like help choosing between the CR75, CR100 and CRT100 for an irrigation, transfer or washing job, call the AES Rewinds team on 01252 515169 or email sales@aesrewinds.com. You can also browse the full Pentax range or all surface mounted pumps.