Pentax CM Centrifugal High Pressure Centrifugal Pumps

Where to Use Pentax CM Pumps

The CM range is at home wherever you need clean water delivered at a useful pressure from a tank, cistern or reservoir. Typical jobs include boosting mains or tank water to a house, workshop or small commercial building, running garden sprinklers and drip irrigation, feeding washing systems and wash-down points, and transferring water between storage tanks. If you are not sure whether you need a booster or a transfer pump, our guide on what a booster pump is explains the difference.

Install the pump on a firm, level base, under cover and as close to the water source as possible. The best arrangement is a flooded suction, with the pump below the water level so water runs into it. If the pump has to sit above the water, fit a foot valve, keep the suction pipe short and airtight, and make sure it is at least the size of the inlet. Our guide to suction lift and NPSH explains why the suction side matters so much.

The CM is built for clean water at pressure, not for dirty water. For water carrying silt, leaves or soft debris, the Pentax CR open impeller pump is the better choice. For an automatic supply that starts and stops on demand, browse our booster pumps.

Frequently Asked Questions

How much pressure will a Pentax CM pump give?

As a rough guide, 10 metres of head equals 1 bar. At zero flow the CM50 reaches 21.5 metres, the CM100/61 33 metres and the CMT 214 50 metres, but the pressure falls as the flow rises. The CM100/61, for example, still gives 25.2 metres at its full 90 l/min. Subtract the height you are pumping up to and the losses in the pipework to find the pressure left at the outlet. Our guide on how to read a pump curve shows how.

Is the Pentax CM self-priming?

No. The pump casing and suction pipe must be full of water before you start it. Install it below the water level, or fit a foot valve and fill the pump through the priming plug. Our guide on how to prime a pump walks you through it. Never run the pump dry, as that damages the mechanical seal. If the pump has to lift water from below, a self-priming pump is easier to live with.

Does the CM pump switch itself on and off?

No. The CM50, CM100/61 and CMT 214 are bare pumps without a pressure switch or flow controller, so they run whenever power is applied. For automatic boosting, add a suitable pressure or flow control, and run the three-phase CMT 214 through a starter with overload protection.

What is the maximum water temperature and pressure?

Pentax rates the CM at up to 90 °C with a brass impeller and up to 50 °C with a Noryl impeller. Maximum operating pressure is 6 bar for the CM50 and CM100/61 and 8 bar for the CMT 214. Smaller CM pumps are commonly supplied with a Noryl impeller, so if you need to pump water above 50 °C, call us to confirm which impeller is fitted before you order.

Is this the same as the Pentax CM 32-160 and similar pumps?

No. Pentax also uses the CM name for its larger end-suction monobloc pumps built to EN 733, with model names such as CM 32-160. The pumps on this page are the compact, single impeller CM range with threaded connections.

If you would like help choosing between the CM50, CM100/61 and CMT 214 for a boosting, irrigation or washing job, call the AES Rewinds team on 01252 515169 or email sales@aesrewinds.com. You can also browse all surface mounted pumps or the full Pentax range.