Grundfos CRN 3 Vertical Multistage Pump

Vertical, multistage centrifugal pump with suction and discharge ports on the same level. CRN is the AISI 316 grade of the CR platform: every wetted part — pump head, base, chambers, impellers, shaft and sleeves — is AISI 316. Because the ports share a centreline, the pump installs in a straight pipe run without an offset.

The CRN 3 frame is rated at 15.4 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.

18 models are offered, from CRN 3-2 to CRN 3-25, covering 1/3 to 5 HP on NEMA 56C, 182TC C-face totally enclosed fan-cooled (TEFC) motors. Adding stages raises head at the same flow without changing the footprint. Connections are 1-1/4 in Victaulic grooved, or 1-1/4 in ANSI 300 lb flanged. Both are rated 362 psi maximum operating pressure.

Why 316 rather than 304. The hydraulics are shared across CR, CRI and CRN, so a CRN 3-3 and the matching CR or CRI model have the same rated duty point. What changes is corrosion resistance. The molybdenum in AISI 316 is what resists chloride pitting, so CRN is the grade for chloride-bearing water, softened or brackish supplies, coastal installations, and process liquids that would pit 304. Where chlorides are not the issue, CRI in 304 does the same hydraulic job for less money, and CR in cast iron less again. For seawater and stronger chloride duty Grundfos offers the CRT range in titanium.

• AISI 316 wetted path — pump head, base, chambers, impellers, shaft and sleeves in EN 1.4401 (AISI 316). The molybdenum content is what resists chloride pitting.
• In-line ports — suction and discharge on the same level, so the pump installs in a straight run without an elbow or offset.
• Cartridge shaft seal — replaced as a complete unit without setting the seal by hand and without special tools.
• Silicon-carbide seal faces — SiC against SiC on both faces in every seal option listed here.
• NSF/ANSI 61 certified for drinking water contact.
• Totally enclosed fan-cooled (TEFC) NEMA C-face motor — 56C, 182TC frames across this range, 60 Hz.
• Two connection styles — 1-1/4 in Victaulic grooved, or 1-1/4 in ANSI 300 lb flanged. Both are rated 362 psi maximum operating pressure.

• HQQE — EPDM. Silicon-carbide faces with an EPDM O-ring, rated −4 °F to 248 °F. The standard water seal: potable water, hot water and glycol. Mineral oils need HQQV.
• HQQV — FKM (Viton). Silicon-carbide faces with an FKM O-ring, rated −4 °F to 194 °F. For mineral oils, fuels and liquids that attack EPDM.

In the Grundfos type key the final letter is the rubber: E = EPDM, V = FKM. Both options use silicon-carbide faces (QQ) and the same cartridge format.

• Chloride-bearing, softened and brackish water, where 304 stainless would be at risk of pitting
• Coastal and marine-adjacent installations
• Reverse osmosis feed and permeate, demineralised and deionised water
• Boiler feed, condensate and chemical dosing skids
• Food, beverage and pharmaceutical process duty
• Industrial process cooling, liquid transfer and pressure boosting