A power-end magnet observation is useful only when it identifies where the material was found and what was actually seen. For NOV Type P maintenance, keep that observation separate from a diagnosis. This guide supplies a record checklist, not an access, cleaning, repair or return-to-service procedure.
What the OEM passage establishes
NOV booklet 25-101131, page 4, describes power-end magnets as collectors of ferrous particles that may originate from moving components' load-bearing surfaces. It calls for cleaning the sump drain-plug magnet assembly and the magnets in the upper lubrication troughs near the pinion bearings during routine power-end oil changes.
This explains the collection function and maintenance context. It does not provide a particle-count limit, a size-based acceptance rule or a remaining-life calculation. Finding material on a magnet is not enough to identify its source component.
Record each location separately
Confirm the installed pump and applicable manual before naming the magnet location. Avoid combining several locations into an entry such as “all magnets normal” if only one was observed. If a location was inaccessible or not inspected, preserve that limitation.
The following are editorial record fields, not extra OEM requirements:
- Equipment tag, model, serial number, manual revision and work-order reference.
- Inspection date and responsible person.
- Magnet location as identified in the applicable equipment documentation.
- Visible material before cleaning, described without an assumed failure mechanism.
- Photographs with the location identified, where safe and permitted; a reference scale if dimensions are being documented.
- Any sample identifier and handling record required by the site's maintenance process.
- Work actually performed under the approved procedure and the condition observed afterward.
- Unchecked locations, uncertain observations, reviewer disposition and follow-up work-order reference.
A photograph without a location or scale should not be converted into an exact particle measurement. Do not replace “not inspected” with “no debris.”
Separate observation from diagnosis
Use factual descriptions of appearance and location. If a comparison with an earlier record is made, retain the earlier record and note differences in inspection conditions. A change in appearance alone does not prove a bearing or gear has failed.
Refer uncertain or concerning findings through the authorized maintenance process. This article does not define a safe-to-run threshold, prescribe laboratory tests or authorize continued operation. The applicable equipment instructions and responsible maintenance personnel determine the next action. An apparently clean magnet cannot establish the condition of the whole lubrication system.
Related equipment and records
NOV 12-P-160 and NOV 14-P-220 are navigation links, not evidence that their lubrication layouts or replacement magnet assemblies are identical. Link the observation to the main-sump cleaning handover when relevant, while keeping the two records distinct.
Before physical inspection, authorized personnel must follow the installed equipment's shutdown, energy-isolation and safe-access requirements. No magnet part number, interchangeability, stock availability or service-life claim is made here.
Source and scope
NOV, How to Treat Your Type P Triplex Mud Pump, document 25-101131, page 4; checked 7 October 2026, Los Angeles time. The collection function and oil-change cleaning context come from this source. The record fields and evidence distinctions are editorial suggestions, not an OEM diagnostic standard.
FAQ
Does collected metal prove that a particular bearing has failed?
No. A magnet observation alone does not establish the originating component or failure mechanism.
Does this source passage define an acceptable particle count?
No. This guide does not invent a count, size or safe-to-run threshold.
Should observations from several magnets be combined?
Keep each identified location separate so the record shows exactly what was inspected.
Does cleaning the magnet complete the maintenance job?
No. Cleaning, review of findings and the applicable return-to-service checks are separate responsibilities.