CN Series
ANSI CN Series Water Centrifugal Pump
End-suction water pump built to ANSI/ASME B73.1 with a full open impeller and ANSI B16.5 flanges
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Solution
Standards and Interchangeability
ANSI/ASME B73.1, ISO 2858, ISO 5199 and BS EN733. What each standard actually fixes, and what that means when a pump is replaced.
The Situation
Why This Matters
A dimensional standard is a promise about the future: that the pump bought today can be replaced in fifteen years without touching the foundation or the pipe spools.
Flowsteer builds to three families of standard — ANSI/ASME B73.1 on the CN series, ISO 2858 and ISO 5199 on the CI and KCP series, and BS EN733 / DIN24255 on the FA series. A plant does not have to adopt all three; it has to know which one it already has.
The standard that matters is the one already in the ground. Matching it is cheaper than changing it.
Three sizes of ANSI end-suction centrifugal pumps from the same hydraulic family
Step by Step
How It Works in Practice
- Identify the standard on the existing pumpThe nameplate, the size designation and the flange pattern together tell you which family the pump belongs to.
- Match the designation, not the brandAn ISO 2858 pump marked 80×50-200 interchanges with any other 80×50-200, regardless of who made it.
- Check the flange class separatelyDimensional interchange does not guarantee flange interchange. ANSI B16.5 150LB and 300LB differ; DIN2501 and ANSI B16.5 differ more.
- Confirm hydraulics as well as dimensionsTwo pumps can share every dimension and still sit on different curves. Check the duty point when the brand changes.
- Decide whether to standardiseIf a plant has three standards, converting to one over successive maintenance cycles usually pays for itself in the spares store.
- Record the decisionStandardisation only works if the next purchase order says which standard applies.
What You Gain
What Changes When You Do This Properly
- Three standards from one supplierANSI, ISO and EN733 series in one catalogue, so standardising does not mean changing supplier.
- Documented interchangeabilityThe ISO CI series states it is fully interchangeable with other brands; that is the design intent, not an afterthought.
- Flange options within the standardANSI 150LB and 300LB on the CN series; DIN2501 or ANSI B16.5 150lb on the FA.
- Smaller spares holdingOne standard means fewer distinct impellers, seals and bearings across the pump population.
Applies To
Pumps This Solution Covers
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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FA Series
FA Series EN733 Horizontal Centrifugal Pump
BS EN733 / DIN24255 end-suction pump, 2 to 1100 m³/h and head to 152 m, for building services fire and irrigation
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DE Series
DE Series Water Centrifugal Pump
Process-duty water pump from DN 25 to DN 400 with flow to 600 m³/h for water and waste water
View specificationsRead Next
Guides on This Subject
Standards Guide
ANSI/ASME B73.1 Explained
B73.1 is a dimensional standard, not a performance standard. Knowing the difference is what makes a replacement pump drop straight onto an existing baseplate.
Read moreStandards 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 moreStandards Guide
EN733 and DIN24255 Explained
Two names, one set of dimensions. Why both still appear on specifications and what they fix on an end-suction pump.
Read moreQuestions
Standards and Interchangeability FAQ
Does a standard guarantee the pump will perform the same?
No. Dimensional standards fix the mounting and connection geometry, not the hydraulic curve. ISO 5199 adds engineering requirements such as shaft deflection and bearing life, but the duty point still has to be checked.
Which standard should a new plant adopt?
Whichever matches the pipework and the local supply chain. In DIN pipe markets EN733 is usually the path of least resistance; in ANSI markets B73.1 is.
Can I mix standards in one plant?
You can, and most plants do, but every additional standard adds a spares line and a set of drawings. Converting to one over time is usually worth doing.
What is the difference between ISO 2858 and ISO 5199?
ISO 2858 fixes dimensions. ISO 5199 is a technical class covering shaft deflection, bearing life, seal chamber design and casing thickness. The CI series is built to both.
Put Standards and Interchangeability to Work on Your Plant
Tell us the pumps you have and the duties they run, and we will say where this applies and what it would change.