Pump Literacy — Retrofits · Interactive

Pump Retrofitting: Things to Consider

Replacing an existing pump with a new one · about 15 minutes
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Training complete

Next retrofit: duty points and configuration, all four dimensions, every side measured, then decide how big the difference really is before anyone writes a PO.

Same duty point doesn't mean it fits

When a new pump replaces an old one, sizing it to the duty point is only half the job. The other half is making sure it physically drops into the space, the piping and the base the old pump left behind. This covers what to collect, how to tell a direct replacement from a major one, and what has to happen before a PO.

7 parts · ~15 minutes 6 pumps to sort, 8 questions
Part 1 · What to collect

Tell us everything about the old pump

This applies any time you're replacing one of these:

End suctionSplit casePipingShort set turbineBooster

We compare the old pump against the new options on two things: its duty points and its configuration. Missing either one is how retrofits go wrong. Check off each item as you'd gather it on a real job.

Why every side? With all of it measured, we can say whether this is a direct replacement, a near direct replacement, or a major one. Guessing from one view or from a photo is how a "perfect match" turns out not to fit.
Part 2 · The four dimensions

A through D: the numbers that have to match

Tap each dimension to see where it's measured.

motor discharge suction CL A B C D D
End suction pump, side view. A schematic, not to scale.
Watch the feet and flange projection. They usually don't match exactly between brands. That's where most "near direct" replacements run into trouble.
Part 3 · Direct, near or major

First, determine how severe the difference is

Every retrofit lands in one of three buckets. The bucket decides how much detailing and planning it takes.

Easiest

Direct replacement

An exact match on every measurement. It's perfect: we just drop the pump in.

If anything doesn't match, it isn't direct, and we have to start getting creative.

No adapting needed
Minor

Near direct

A–D are the same, with small differences such as:

  • the feet
  • height on the skid
  • suction or discharge diameter

Solutions: a base plate or single spool adder, or a custom piece to adapt. Not the end of the world, but it takes consideration.

Detailing and planning recommended
Gets involved

Major

Any of these:

  • suction or discharge orientation or position is different
  • overall length is different
  • a major dimension (A–D) is different

Could mean a new baseplate, piping, routing, or site-specific accommodations.

Detailing, planning and drawings REQUIRED
Doesn't have to be the same part number. A direct replacement can be a different product with the same dimensions and bolt pattern. If the exact SKU can't be found, look through the specs on other options.
Part 4 · Sort it

Direct, near direct, or major?

Each pump below has been measured against the old one. Get 5 of 6 right to finish this part.

Part 5 · From the field

Two retrofits that taught us something

Both are real Rhino jobs. Read each one, decide what went wrong, then open the lesson.

Story 1 · The "perfect match"

It looked just like the old pump

The rep thought they had a perfect match. Optically, the new pump looked similar to the old one, and some of the dimensions were close.

In reality it didn't even meet the "near direct" standard. 3 of the 6 dimensions were different, and the existing piping couldn't be modified. There was no physical space in the piping system for it to work.

The rep then had to find a true direct replacement. It wasn't the same product number: it was a different pump with the same dimensions and bolt pattern.

The lesson
Looking similar and "close" dimensions aren't a match. Measure every dimension and compare them all. And when the exact pump can't be found, search the specs of other products for one that matches.
Story 2 · Same type, same duty points

A split case is a split case, right?

A rep sized a split case pump on duty points alone and picked the same type of pump, assuming "same type, same duty points" meant the two were interchangeable.

Later we found the suction and discharge diameters were different, and so was the flange-to-flange overall length. We didn't have all the information on the old pump and didn't find out until later.

True detailed it. It needed major accommodations: center to shaft, height, piping, spools, a riser, and a coupling guard.

The lesson
If everything you can see is off, there's a good chance the deeper things are off too: piping, skid, pedestal, everything. For a major difference, build a rough model and confirm it can be done before the PO, then do the detailed work after. Make sure you know every difference exactly.
Part 6 · Before the PO

Can it be done? Answer that first.

Before a PO, the goal is to find out if the retrofit is feasible without doing too much work we aren't paid for.

1 · CollectDuty points, configuration, drawings if available, and A–D from every side.
2 · CompareOld pump vs. new options, dimension by dimension.
3 · VerifyRuss or Carl confirms whether it's direct, near direct, or major.
4 · PlanMajor: rough model to prove it can be done, then full drawings and detailing.
DrawingsA must for a major change. For a near direct match, whether drawings are needed depends on the job, so ask.
Don'tAssume same type plus same duty points means interchangeable, or call it a match because it looks right.
Part 7 · Knowledge check

Eight questions to finish

Score 7 or more to pass.

Built from the Retrofitting Training notes. When you're not sure how big the difference is, ask Russ or Carl before you quote.

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