Grundfos CME 5-A Horizontal Multistage Pump, Cast Iron / 304 Stainless Steel

Horizontal, multistage centrifugal pump with the motor close-coupled to the pump end and the suction port on the end of the pump. CME is the CM pump end with an MLE motor on top: a motor with the frequency converter built into its terminal box, so the pump varies its own speed instead of running flat out against a throttling valve. It lies on its feet on a horizontal base, which suits a plant room where headroom is short and floor space is not.

A pump curve plots what the pump adds to the pressure already at its inlet, not the pressure you will read at the outlet. On a city main holding 40 psi, a pump adding 60 psi gives about 100 psi downstream. On a gravity-fed tank the inlet contributes almost nothing and the curve is close to what you get. Size on the boost required, then let the drive hold it.

The CME 5 frame is rated at 24.8 GPM. The family number is Grundfos’s nominal duty in cubic metres per hour, not a GPM figure — size the pump from the rated head table below, not from the model number.

4 models are offered, from CME 5-2 to CME 5-5, covering 1-1/2 to 3 HP on NEMA close-coupled motors. Adding stages raises head at the same flow without changing the footprint. Connections are 1-1/4 in NPT female suction and 1 in NPT female discharge, and the pump is rated 145 psi maximum operating pressure.

Where the cast iron sits. On the -A build the pump housing is cast iron and the impellers, shaft and chamber parts are AISI 304. That is what makes it the lowest-cost CME, and it is also why the maximum operating pressure is 145 psi rather than the 232 psi the all-stainless builds carry. On a potable system where iron pick-up matters, choose the -I build.

• Cast Iron / 304 Stainless Steel — cast iron pump housing with AISI 304 stainless internals.
• Horizontal close-coupled build — motor and pump end on one shaft, on feet, so no coupling alignment and no separate baseplate to grout.
• Multistage hydraulics — head is set by stage count at a fixed frame flow, so the duty point is chosen without oversizing the motor.
• Frequency converter built into the motor — no separate drive panel, no drive-to-motor cable run and no commissioning step to tell a generic drive what motor it is driving.
• 2900-4000 rpm operating speed range — the drive works above and below the fixed 3480 rpm a CM turns, so one pump covers a band of duty rather than a single point.
• Soft starting on every start — ramping up under drive control takes the mechanical shock off the coupling and the water-hammer shock off the pipework.
• Cartridge-format shaft seal — AQQE or AQQV, replaced without setting the seal by hand.
• WRAS, ACS, NSF61 approvals for drinking water contact.
• 145 psi maximum operating pressure on this material build.
• 1-1/4 in NPT female suction and 1 in NPT female discharge — threaded, so no companion flanges to order.

• AQQE — EPDM. Carbon against silicon carbide with an EPDM O-ring. The standard water seal: potable water, hot water and glycol. Mineral oils need AQQV.
• AQQV — FKM. Carbon against silicon carbide with an FKM O-ring, for mineral oils, fuels and liquids that attack EPDM. Note that FKM carries the lower temperature ceiling of the two.

• AQQE — −4 °F to 194 °F.
• AQQV — −4 °F to 194 °F.

In the Grundfos type key the final letter is the rubber: E = EPDM, V = FKM. The seal is a specification decision, not a preference — it changes the published temperature limit.

• Constant-pressure boosting on clean potable water where demand swings through the day
• Irrigation and washdown duty with several outlets opening and closing
• Cooling and condenser loops that spend most of their life at part load
• Retrofits replacing a fixed-speed pump and a throttling valve with one unit

Select the HP and voltage, then the seal, then the model. Each combination is a distinct Grundfos part number, listed in the table above and shown in the SKU of the selected variant.

The picker shows only the combinations Grundfos publishes.