Vertical Sump Pump Setting, Shaft Length & Steady Bearing Selection Guide

This field guide shows how to collect enough information for a replacement pump or critical spare without turning an estimated site dimension into a manufacturing dimension.

Define the terms before measuring

The supplier’s GA or sectional drawing should control the final definition. If the original drawing is unavailable, create a field sketch and label every reference point before taking dimensions.

Field measurement procedure

1. Establish one datum. The top surface of the support plate is often convenient, but use the drawing datum when one exists.
2. Record the pit. Measure pit depth, pit opening, floor clearance and any sloped or obstructed area.
3. Record liquid levels. Mark minimum operating, normal and high liquid levels from the same datum.
4. Locate the hydraulic end. Measure to the casing, suction cover or centreline datum specified by the drawing.
5. Document the column. Record every section, connection type and orientation feature.
6. Document the shaft. Record each section, coupling, thread/key, bearing journal and impeller attachment.
7. Locate each steady bearing. Measure positions from the same datum and identify housing and bearing material.
8. Map the discharge. Record size, orientation, centreline, flange standard and support-plate penetration.
9. Check removal space. Measure overhead and lateral clearance for withdrawing the assembled pump or shaft sections.

Photograph the tape, scale or measuring tool at the labelled reference points. Mark estimated or inaccessible dimensions as estimates; do not mix them with verified values.

How setting relates to shaft and column length

There is no universal equation that converts pit depth directly into shaft length. The assembly may include a support plate, column flanges, bearing housings, shaft couplings, casing geometry and suction components. Each adds an interface that must follow the pump drawing.

A useful dimensional chain starts at the chosen datum and lists every axial segment in order. The sum can then be checked against the overall drawing dimension. If the segment sum and the overall setting disagree, stop and resolve the reference points before releasing a shaft or column.

Illustrative measurement example

This example demonstrates the method and is not a pump design recommendation.

A sump is measured at 3,600 mm from the top of the support plate to the floor. The minimum liquid level is 900 mm below the plate. The installed GA defines pump setting to a casing datum 250 mm above the floor, so the drawing-defined setting is not the same as pit depth. A strainer and required floor clearance occupy the remaining space.

The field sheet records those values separately. Steady-bearing positions are measured from the top of the plate rather than from the nearest column joint. Shaft and column sections are then checked against the GA dimensional chain. This produces traceable inputs; writing “3.6 m vertical pump” does not.

Steady-bearing selection is an engineering decision

Steady bearings support the lineshaft between the thrust bearing and hydraulic end. Quantity, spacing and material depend on the pump design, shaft diameter, speed, total setting, process fluid, solids, temperature and lubrication arrangement. More bearings are not automatically better, and copying spacing from a different size can create alignment or service problems.

For a replacement bearing, provide:

• Pump model, size and total setting
• Shaft diameter and bearing-journal dimensions
• Housing/register dimensions and axial length
• Existing bearing material and lubrication arrangement
• Fluid, temperature, solids and dry-running history
• Photographs showing wear direction, deposits and damaged surfaces

The wear pattern matters. Uniform bore wear, one-sided wear, scoring, heat damage and chemical attack suggest different causes. Replacing the bearing without investigating shaft runout, alignment, lubrication or process compatibility can repeat the failure.

Match materials to the actual process

Avoid service labels such as “wastewater” or “chemical.” Record fluid composition, concentration, pH where relevant, temperature, chlorides or contaminants, solids size/concentration and whether conditions change during cleaning or upset operation. These inputs affect wet-end metallurgy, shaft material, bearing material and vapour/sealing arrangements.

For alloy parts, specify the required casting or wrought grade appropriate to the component. Material selection must be based on the real environment, not only the material used in the failed part.

Build a quotation-ready RFQ

The quotation should return a marked GA or dimensional schedule showing the proposed setting, shaft/column sections and bearing locations. Unverified field dimensions should remain approval hold points.

Reliability review before ordering

A dimensional match does not address insufficient submergence, dry running, solids accumulation at the suction, shaft vibration, unsuitable bearing material or restricted removal clearance. Include operating history and failure photographs in the review, especially when the same part has failed more than once.

Use the Vertical Process Pumps category for the complete-pump path. For an installed spare, begin an OEM part-number cross-reference.

FAQ

What if the original drawing is unavailable?

Create a labelled field sketch, define one datum, and provide nameplate and installation photographs with measured and estimated values clearly separated.

Can a steady bearing be supplied separately?

Yes, after the shaft journal, housing, setting, bearing location, material and process conditions are verified.

Is pump setting the same as pit depth?

No. Pit depth is a civil dimension; pump setting is a supplier-defined pump dimension between stated drawing datums.

Sources and review method

Measurement definitions ultimately depend on the supplier’s controlled drawing. As a model-specific example, the official Goulds 3171 IOM describes a vertical submerged-bearing pump with drive-unit groups and lineshaft bearing arrangements. This guide uses that architecture to explain the review method but does not apply 3171 dimensions to other vertical pump designs.

For a model-specific commercial page, see the 3171 vertical sump and process pump.

Editorial note

Prepared by the ANSI Pumps Pro editorial team from official OEM literature and the replacement-review workflow used by ANSI Pumps Pro / Yingsiman. Last source review: August 9, 2026. Final setting, material, fit and hydraulic selection remain subject to engineering verification. Referenced brand and model designations remain the property of their respective owners and are used only for identification and replacement-reference purposes.

Need a second check on the recorded dimensions? Measure Pump Setting

For a model-specific data package, see the Goulds 3171 replacement-data guide. A complete replacement review should also include the applicable engineering contact details.