TL;DR
Record NOV Type P knocking as an observed symptom first; keep possible causes separate from confirmed findings.
- Use the OEM fluid-end and power-end categories to organize the review.
- NOV page 23 prioritizes fluid-end checks before major power-end investigation.
- A sound, pressure fluctuation or maintenance history alone does not confirm a failed part.
- Any inspection or repair must follow the applicable equipment procedure and authorized safety controls.
This is an evidence worksheet, not a diagnosis, permission to continue running or an adjustment instruction.
Scope: a review record for Type P equipment
Use this guide when preparing a technical handover for a NOV Type P pump. Match the nameplate model and serial number to the applicable manual and configuration. The primary reference is NOV booklet 25-101131, page 23; it does not identify the condition of your installed pump.
The record fields below are editorial recommendations. They do not establish acceptance limits, inspection intervals, replacement requirements or settings. No numerical pressure or clearance limit is adopted here. Follow the equipment-specific procedure for those decisions.
How should possible causes be grouped?
Keep the two OEM categories distinct. The following is a selective summary, not a complete reproduction of NOV page 23:
- Fluid end: pulsation control, valves/seats, piston and rod attachment, suction supply or entrained gas, and restrictions.
- Power end: gears, crosshead/pin/liner, bearings and crankshaft.
A useful worksheet has separate columns or fields for “source-listed possibility,” “actual evidence” and “review outcome.” Do not mark a component defective merely because it appears in a source category. If a finding remains unsupported, label it pending and identify who will assess it.
What evidence belongs in the handover?
Describe what was observed and how it was obtained. Avoid changing “knocking reported near the pump” into “bearing failed.” Record the observation time, available operating context and the named observer or instrument. If a reading is copied from an existing log, retain its units and origin; do not fill missing readings with estimates.
Separate earlier maintenance records from present findings. A past valve replacement can help locate documentation, but it does not identify today's cause. Where documents disagree, record both references and leave the discrepancy unresolved until the responsible reviewer confirms applicability.
Only use observations gathered under an approved procedure. Keep guards in place for authorized operating observations. Intrusive checks require authorized personnel, shutdown, energy isolation and verified pressure release as applicable. Do not loosen a joint, remove a cover, adjust a dampener or restart equipment to complete this worksheet. Follow the site's abnormal-condition procedure if symptoms arise.
Evidence checklist
These fields support a traceable review:
- Identity: pump model, serial number, applicable manual and configuration reference.
- Symptom: observation time, location description, context and reporting method.
- Evidence: existing logs or permitted images, source, units and what remains unavailable.
- Classification: fluid-end or power-end possibility, with the OEM page reference; leave uncertain classification open.
- Finding: confirmed by whom, by which approved assessment, or still pending.
- Handover: responsible reviewer, unresolved questions and the next authorized action.
For catalogue navigation see NOV 12-P-160 and NOV 14-P-220. A catalogue page is not a fault finding or approval for a replacement part.
FAQ
Does knocking prove that a power-end part has failed?
No. Keep the reported symptom separate from a confirmed finding, and use the applicable procedure and evidence to assess the cause.
Is this the complete OEM troubleshooting checklist?
No. The cause groups are a selective summary. Consult the original page and the applicable equipment documentation for the full review.
Can this article supply a pressure or clearance setting?
No. It adopts no numerical setting or acceptance limit. Confirm the model, configuration and applicable OEM procedure.
Should missing evidence be filled with an estimate?
No. Mark it unavailable or pending, retain the known source information and assign the unresolved question to the responsible reviewer.
Source and related records
Primary source: NOV — How to Treat Your Type P Triplex Mud Pump, 25-101131, page 23, Pump Knocking. Checked on 8 October 2026, Los Angeles time. The original page image and extracted text were checked. Cause categories and review priority are OEM information; the worksheet and evidence-handling suggestions are editorial additions.
Related records: discharge pressure-gauge observations and valve/seat pairing records. These support documentation handover and do not turn an observation into a diagnosis.
Next step
For a technical documentation enquiry, provide the pump identity, applicable manual reference and existing observation records. State which findings are confirmed and which questions remain open. Request equipment-specific documentation before deciding on a part or corrective action.