Grundfos VLS Vertical In-Line Split-Coupled Pump

The VLS is a single-stage centrifugal pump built vertically in the pipe: suction and discharge sit on one centerline, the pump stands on its own base on the floor, and a standard motor sits on a bracket above, joined to the pump shaft by a split coupling. It is Grundfos’s PACO design for large circulating and transfer duties where floor space is tight: chilled and condenser water, heating loops, cooling towers and water supply. Every build runs at 1800 RPM, and Grundfos trims the impeller to the flow and head the system needs.

• Spacer coupling: the mechanical seal comes out without removing the motor
• Double volute for lower radial load, quieter running and longer seal and bearing life
• No inertia base, flexible connectors or foundation grouting needed
• Impeller trimmed to your duty point within the motor HP
• Case wear rings and a suction baffle for efficiency and quiet running

Features from Grundfos leaflet VLSE/VLSC (LVLCSL01, 07.2024), which uses this VLS pump with an integrated or separate drive.

Pick the model whose curve passes through your duty point, then open its table. Each row is one impeller diameter Grundfos publishes for that model at 1750 RPM; every figure is the total head the pump adds at that flow. Grundfos trims the impeller to your duty point, and the motor HP sets the largest impeller a build can carry: the dashed lines on each curve in the image gallery mark the motor size each impeller needs.

All figures from the 1750 RPM curves in the Grundfos PACO VLS data booklet, 50/60 Hz, pp. 21-32, digitized and rounded down. PSI = feet ÷ 2.31.

Head in feet. Flows are the points nearest 20%, 50% and 75% of the largest impeller’s curve, then its end. Bold = the last column that impeller’s curve reaches; — = beyond its end. Page numbers refer to the data booklet in the Data Sheet tab.

VLS 2095A, 30125, 40129 and 40159: the data booklet prints no curve for these four models. Email us your duty point and we will confirm the model and impeller with a Grundfos selection.

• The pump stands on its own base; Grundfos requires no inertia base or grouting for the VLS.
• Fit isolating valves on both sides, and support the piping so the pump housing carries no pipe stress.
• Fill and vent the pump before starting; never run it against a closed discharge valve.
• Keep a minimum flow of 10% of the best-efficiency flow at all times; add a bypass where the discharge can close.
• No more than 20 starts per hour.

From Grundfos VLS Installation and Operating Instructions, sections 7-9.

Chilled and condenser water, heating and district heating, air-conditioning circulation, cooling towers and data center cooling, water supply and pressure boosting, and industrial circulation and transfer.

Standard cast iron and bronze build (material code CB) from the Grundfos PACO VLS data booklet, 50/60 Hz, p. 10. Ductile iron, all-bronze, nickel-aluminum bronze and stainless steel builds are factory options.

Grundfos lists one impeller, one mechanical seal, the wear rings, the volute O-ring or gasket, the seal-cap O-ring and the shaft bushing as the recommended spare set. Send us the pump nameplate and we will quote the set.