Grundfos CR Series Sizing Guide: All 16 Sizes Compared (2026)

Grundfos CR Pump Sizing Guide — How to Choose Across All 16 Sizes

A complete buyer's guide to the Grundfos CR vertical multistage centrifugal pump range — flow, head, HP, materials and applications across all 16 NEMA 60 Hz sizes from CR 1s to CR 255.

The Grundfos CR is the most installed vertical multistage centrifugal pump in the world. With 16 size frames covering flows from 4 to 1,500 GPM and heads up to 910 ft, plus three material codes (cast iron, 304 stainless, 316L stainless) and matching variable-speed E-Pump siblings, it solves nearly every industrial water pumping problem from boiler feed to reverse osmosis. This guide walks through every size in the 60 Hz North America range and shows how to pick the right model for your duty point.

CR / CRI / CRN — Full Range at a Glance

Model	Max flow (GPM)	Max head (ft)	Motor (HP)	Max stages	Best for
CR 1s	4	420	0.5 – 1	36	Dosing, OEM, very low flow boost
CR 1	8	670	0.5 – 2	36	Light booster, RO permeate boost
CR 3	18	680	0.5 – 3	36	Small booster, light industrial
CR 5	32	720	0.5 – 5	36	Small commercial, RO pre-feed
CR 10	60	650	1 – 15	22	Commercial boost, light industry
CR 15	92	700	2 – 30	17	Industrial boost, boiler feed
CR 20	124	720	3 – 30	17	Mid-industrial process
CR 32	190	800	5 – 60	14	RO feed, cooling tower, large boiler
CR 45	260	800	10 – 75	13	Mid-large industrial
CR 64	380	700	15 – 100	9	Large industrial, district heating
CR 95	570	700	25 – 150	7	Large pressure boosting
CR 125	750	900	30 – 200	7	Municipal, large RO trains
CR 155	900	910	40 – 250	7	Municipal high-pressure
CR 185	1100	900	60 – 300	6	Large municipal/industrial
CR 215	1300	900	75 – 350	5	Very large industrial
CR 255	1500	900	100 – 400	5	Largest CR — municipal RO/SWRO

Material Code: Which Stainless?

Code	Pump head & base	Internals	Used for
CR	Cast iron	AISI 304	Clean cold/warm water, boiler feed, irrigation, HVAC
CRI	AISI 304	AISI 304	Demin water, sanitary, light corrosion, food & beverage
CRN	AISI 316L	AISI 316L	RO & SWRO feed, potable water, chlorides, pharma, chemicals

Tip: If chlorides exceed 200 ppm or temperature is sustained above 140 °F, jump from CR/CRI to CRN — pitting and stress-corrosion cracking risk in 304 stainless rises sharply above that envelope.

Fixed Speed vs Variable Speed (E-Pump)

Every CR/CRI/CRN size has a matching CRE / CRIE / CRNE E-Pump with an integrated MLE IE5 permanent-magnet motor and onboard variable frequency drive. Choose fixed-speed when the duty point is constant; choose the E-Pump when demand modulates — savings are typically 30–70 % versus a fixed-speed pump throttled with a control valve.

Read: CR vs CRE in depth

Five Steps to Size Your Grundfos CR

Establish design flow (GPM). Take the worst-case demand — peak booster flow, full RO train feed flow, design irrigation flow.
Calculate total dynamic head (ft). Add static lift, pipe and fitting friction, valve losses, and the pressure required at the discharge point.
Pick the material code. CR for clean water, CRI for mild corrosion / sanitary, CRN for chlorides / RO / potable.
Decide fixed vs variable speed. Variable-speed E-Pump if the duty modulates more than 20 %; fixed CR otherwise.
Read the curve. Cross GPM (x-axis) with ft head (y-axis) on the family curve — the size that brackets your duty point is the answer. Stage count gives the exact head.

Application Quick-Map

Boiler feed: CR/CRN 5, 10, 15, 20, 32 — with HQQV seal for hot service.
Reverse-osmosis pre-feed (city water): CRN 3, 5, 10, 15, 20.
Reverse-osmosis high-pressure (brackish): CRN 15, 20, 32, 45 — or BM module for seawater.
Cooling-tower makeup: CR 32, 45, 64 — fixed or variable speed.
Commercial pressure boosting: CRE 5, 10, 15 in a Hydro Multi-E bank.
Irrigation (large turf): CR 32, 45, 64, 95 — with CUE drive for variable demand.
Light industrial process: CRI 3, 5, 10, 15.

Need Help Sizing?

ForeverPure Place is an authorized Grundfos partner with engineering staff who run the Grundfos Product Center selector daily. We can size, quote and ship — with stock and quick-ship lead times across most CR configurations.

Request CR Sizing & Quote Browse Grundfos Catalog

Frequently Asked Questions

What is the smallest Grundfos CR pump?The Grundfos CR 1s is the smallest, delivering up to 4 GPM at 420 ft of head with motors from 0.5 to 1 HP. It is used for small dosing, low-flow booster and OEM applications.

What is the largest Grundfos CR pump?The Grundfos CR 255 is the largest, delivering up to 1500 GPM at 900 ft of head with motors from 100 to 400 HP. It is used in municipal water boosting, large industrial process and high-pressure RO trains.

How many stages do CR pumps have?Stage count varies by size: CR 1s through CR 5 can have up to 36 stages, CR 32 up to 14, CR 64 up to 9, and CR 255 up to 5 stages. More stages produce more head at lower flow.

Are CR pumps 50 Hz or 60 Hz?Both are available. The Grundfos CR North America range ships at 60 Hz with NEMA motors as standard; 50 Hz IEC versions are available on request and are common outside North America.

What is the difference between CR, CRI and CRN?CR has a cast-iron pump head and base with 304 stainless internals — the workhorse for industrial water. CRI is all 304 stainless (head and base included) for mildly aggressive liquids. CRN is all 316L stainless for RO, desalination, potable water and corrosive chemistry.

Can I run a Grundfos CR with a VFD?Yes — pair it with a Grundfos CUE external VFD, or order the integrated E-Pump variant (CRE / CRIE / CRNE) which has the MLE motor + drive built in.

What seal types are available?Standard HQQE (Carbon/SiC with EPDM) for cold and warm water, HQQV (Carbon/SiC with FKM) for hot water and aggressive media, and double cartridge seals for hazardous duty.

How do I size a Grundfos CR?Establish design flow (GPM) and total dynamic head (ft) at the duty point, then read across the CR family curve chart. ForeverPure can run the sizing free of charge with the Grundfos Product Center selector.