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Bare-shaft centrifugal pump units wrapped and staged before motor mounting
CI Series

ISO CI Series Water Centrifugal Pump

ISO 2858 and ISO 5199 back-pull-out end-suction pump, fully interchangeable with other ISO brands

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Overview

ISO 2858 sets the dimensions and ISO 5199 sets the engineering class. Build to both and the pump is interchangeable on the pipe rack and defensible in the specification.

The CI series is an end-suction centrifugal pump built to ISO 2858 with back-pull-out construction. Sizes run from 50×32-160 through to 250×200-400, with capacity to 500 m³/h and head to 80 m.

Back-pull-out means the bearing frame, shaft, seal and impeller withdraw as one assembly while the casing stays bolted into the pipework. Suction and discharge pipes are never broken to change a seal, which is what turns a two-day seal job into a two-hour one.

The series is designed to be fully interchangeable with other ISO 2858 pumps. For plants running a mixed fleet, that means one spare impeller and one spare seal can cover pumps from more than one maker.

ISO Water Centrifugal PumpsCI Centrifugal Pumps

ISO 2858 CI series back-pull-out end-suction centrifugal pump

ISO 2858 CI series back-pull-out end-suction centrifugal pump

Key Benefits

What This Pump Does Better

  • Back-pull-out maintenanceThe rotating assembly comes out through the back of the casing with the pipework untouched, so seal and bearing work happens without breaking flanges.
  • Interchangeable with other ISO brandsISO 2858 fixes the hydraulic and mounting dimensions, so a CI pump takes the place of any other ISO 2858 pump of the same designation.
  • Built to the ISO 5199 engineering classISO 5199 covers shaft deflection, bearing life and seal chamber design rather than just dimensions, which is what a specifying engineer is usually asking for.
  • Standardised sizes cut the spares listEleven designations from 50×32-160 to 250×200-400 cover most water duties with a shared parts philosophy.
  • Stainless options for aggressive waterSS304 and SS316 wetted parts extend the series beyond clean water into treated and chemically dosed streams.
In the Works

The Pump and How It Is Built

Cutaway demonstration pump showing shaft, bearing housing, mechanical seal and closed impellerStainless steel centrifugal pump volute casings staged on a pallet after casting and machiningEnd-suction centrifugal pump coupled to a flange-mounted motor on a common baseplateBare-shaft centrifugal pump units wrapped and staged before motor mounting
Application Scenarios

Where This Pump Is Put to Work

  • Water treatment plant transferMoving raw, settled and filtered water between process stages where an ISO footprint is specified.
  • Process water circulationClosed and open circuits in industrial plants running on metric pipework.
  • Effluent and dosed waterSS304 and SS316 builds for treated effluent and chemically conditioned water.
  • Fleet standardisationReplacing mixed-brand ISO 2858 pumps with one series to shrink the spares holding.

Who It Is For

  • Plant engineers running a mixed fleet of ISO 2858 pumps who want one spares philosophy instead of four.
  • Consulting engineers whose specification calls out ISO 2858 dimensions and ISO 5199 engineering requirements.
  • Maintenance teams who need seal changes done inside a shift without breaking pipework.
Problems It Solves

What It Is Chosen to Fix

  • Seal changes that mean breaking pipeworkBack-pull-out construction takes the rotating assembly out of the back of the casing; the flanges stay bolted.
  • A spares store full of one-off partsISO 2858 interchangeability lets one impeller and seal cover pumps from several manufacturers.
  • Corrosion on treated or dosed waterSS304 and SS316 wetted parts replace cast iron where the water attacks ferrous material.
  • Energy cost on continuous dutyThe series is built around high hydraulic efficiency, which matters most on pumps that run around the clock.
Technical

Features and Specifications

Every value below is taken from the Flowsteer product catalogue. Values the catalogue does not publish are marked TBC rather than estimated.

Technical Features

  • ISO 2858 dimensional standard
  • Back-pull-out end-suction construction
  • Single mechanical seal
  • Cast iron, ductile iron and SS304 casings available
  • Compact footprint for tight pump rooms
  • Fully interchangeable with other ISO 2858 pumps

Specifications

Specifications
Pump typeEnd-suction, single-stage, back-pull-out
Design standardISO 2858 / ISO 5199
Size range50×32-160 up to 250×200-400
Capacity (Q)Up to 500 m³/h
Head (H)Up to 80 m
Shaft sealSingle mechanical seal
Casing materialsCast iron, ductile iron, SS304
Wetted materialsCI, SS304, SS316
SpeedTBCnot published on the source catalogue
Operating temperatureTBCnot published on the source catalogue
Materials

Wetted Materials and What They Are For

  • Cast iron (CI)The standard build for clean and treated water at ambient temperature.
  • Ductile ironSpecified where casing strength or pipe loading exceeds what grey iron will carry.
  • SS304For treated effluent, softened water and mildly aggressive process water.
  • SS316Where chloride content or chemical dosing rules out 304.
Stainless steel centrifugal pump volute casings staged on a pallet after casting and machining
Casings are cast and machined before assembly. The material decision is made from the water analysis, not from the duty point.
Technician connecting a centrifugal pump to the performance test rig
Pumps are connected to the test rig before shipment. Tell us what test documentation your project requires and we will confirm what can be supplied.
Customisation

What You Can Specify on This Pump

  • Wetted material: CI, SS304 or SS316
  • Casing: cast iron, ductile iron or stainless steel
  • Bare shaft pump or complete set with motor, coupling and baseplate
  • Size selection across the 50×32-160 to 250×200-400 range to match the duty point

Certifications, production capacity and export markets are not published in the Flowsteer catalogue, so this site does not state them. Tell us what your project needs evidenced and we will confirm in writing.

How It Compares Within the Range

SeriesPublished EnvelopeBest Suited To
ISO CI SeriesISO 2858 / ISO 5199, closed impeller, to 500 m³/h and 80 mISO-specified plants and mixed ISO fleets
ANSI CN SeriesANSI/ASME B73.1, open impeller, to 400 m³/hPlants standardised on the American dimensional standard
KCP SeriesISO-style construction in PP, PE and UHMW-PEWater that attacks metal wetted parts
Use Guide

Getting This Pump Right on Site

  • Select the designation from the duty point first — the 50×32-160 to 250×200-400 range is a hydraulic grid, not a continuum.
  • Confirm the existing pump's ISO 2858 designation before ordering a replacement; the designation, not the brand, is what has to match.
  • Plan seal changes around the back-pull-out feature: keep clear access behind the bearing frame equal to the shaft length.
  • Where the water is chemically dosed, specify the wetted material from the dosed condition, not the raw water analysis.
Related

Industries Solutions and Guides

Partly assembled centrifugal pumps lined up on the assembly floor
Industry

Waste Water Treatment

Open impellers, polymer wetted parts and vertical sump pumps for screened sewage, return sludge, effluent and pit drainage.

Read more
ISO 2858 CI series back-pull-out end-suction centrifugal pump
Standards Guide

ISO 2858 vs ISO 5199

One standard says where the holes go. The other says how long the pump should last. Specifications usually need both.

Read more
Also in the range

Related Products

Questions

ISO CI Series Water Centrifugal Pump FAQ

What is the difference between ISO 2858 and ISO 5199?

ISO 2858 is dimensional — it fixes sizes, flange positions and shaft heights so pumps interchange. ISO 5199 is a technical class covering shaft deflection, bearing life, seal chamber dimensions and casing thickness. The CI series is built to both.

Will a CI pump replace another manufacturer's ISO 2858 pump?

Yes, that is the design intent. If the designation matches — for example 80×50-200 — the mounting dimensions, flange positions and shaft height match too.

What is the maximum head and flow?

Up to 500 m³/h and up to 80 m across the range. A single size will not reach both limits, so send us the duty point and we will name the designation.

Why choose SS316 over SS304?

SS316 contains molybdenum and resists chloride pitting far better than SS304. If the water is brackish, chlorinated beyond potable levels or chemically dosed, 316 is the safer wetted material.

How long does a seal change take on a back-pull-out pump?

The pipework stays bolted to the casing, so the job is limited to uncoupling the driver, withdrawing the rotating assembly and refitting. The pipe breaking and re-alignment that dominate a conventional seal change disappear.

Request a Quotation for the CI Series

Send the duty point and the liquid description and we will confirm the size, the materials and any specification this page marks TBC.

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