A casting number identifies the housing, and one casting typically serves several pump variants, so it narrows the search without ever settling it. Treat the numbers on a pump in this order: the nameplate or data plate gives the model and the build, a stamped number on a machined face or on the regulator identifies the specific build or setting, and the cast-in number identifies the body family. Order from the nameplate or the stamped number where either survives; use the casting number only to confirm the family, and always confirm against the machine model, serial number and the pump's displacement and control type.
The three markings on a pump, and what each one settles
| Marking | What it identifies, and how to use it |
|---|---|
| Casting number (raised, cast into the body) | The housing family. Confirms which group of variants a pump belongs to. Never sufficient on its own to order. |
| Stamped or etched number (on a machined pad or the regulator) | The specific build. Applied after assembly, so it reflects displacement, control type and setting. Quote this where it survives. |
| Data plate or nameplate | The fullest identification: model, displacement, control type, rotation, manufacturer. Photograph it before it is lost. |
| Control arrangement (from the piping and the machine documentation) | Decides compatibility between pumps of the same displacement. Not visible in any of the numbers on the body. |
| Machine model and serial number | Ties the pump to the right build of the machine and resolves supersessions. Always quote it. |
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Request a quoteFrequently asked
Can I order a pump from the casting number alone?
No. The casting number identifies a housing family that is shared by several pumps differing in displacement, control type and pressure setting, so a pump ordered from it alone may bolt up perfectly and still be the wrong unit. Use the casting number to confirm the family, and order from the data plate or the stamped build number, together with the machine model and serial number.
My data plate is gone. What do I do?
Work from the stamped number on the machined pad or the regulator, which is the build identification and is much harder to lose than a plate. If that is also illegible, send photographs of the pump from several angles, together with the machine model and serial number, and a supplier can usually identify the variant from the control arrangement and the port layout. Do not order from the casting number and hope.
Why do two pumps for the same machine model look identical but cost differently?
Because they are different variants. Displacement, control arrangement, regulator type and the pressure rating all change between builds, and a pump with a different control will not run the machine properly even though it fits. The price difference reflects a genuine difference in the unit, which is why the model name alone is not enough to price or to order a pump.