How We Identified a Grundfos Vertical Multistage Pump Seal Without a Part Number
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Chloe Walker
- Technical Resources
- Aug 3, 2026
How We Identified a Grundfos Vertical Multistage Pump Seal Without a Part Number
The Challenge
A motor rewinder contacted us after stripping down a Grundfos vertical multistage pump during a motor rewind. As is often the case, the mechanical seal had been removed before the pump reached us, but there was no pump model or part number available to identify a replacement.
The customer wanted to source a high quality aftermarket seal that would provide reliable performance while helping to keep the repair cost competitive, provided it was suitable for the application.
This is a common challenge for motor rewinders. Pumps frequently arrive with little or no identification, leaving the physical seal as the only starting point for selecting the correct replacement.
Why Replace the Mechanical Seal During a Motor Rewind?
Our pump engineer, Kevin, explains:
“Once a pump has been dismantled for a motor rewind, it's good practice to replace the mechanical seal before reassembly. Mechanical seals are wear components, and fitting a new seal helps maximise reliability while reducing the risk of the pump needing to be stripped down again soon after being returned to service.”
Our Solution
Using the original seal for reference, we:
» Examined the seal's design, dimensions and component materials.
» Identified the correct seal specification from its physical characteristics.
» Recommended a 16 mm CAR/SIL/EP mechanical seal as a suitable replacement for the application.
The Result
The motor rewinder was able to complete the repair without needing the original pump model or OEM part number. By accurately identifying the seal and supplying a suitable replacement, the rebuild stayed on schedule, helping minimise downtime and giving their customer confidence in the long term reliability of the repair.
