A coolant reservoir service entry does not show which rod chambers were checked. Keep a location-specific cleanliness record alongside that work order so the handover identifies what was observed, what was cleaned and what remains unverified. This is a documentation checklist, not a cleaning or startup procedure.
What the OEM passage says
NOV document 25-101131, page 15, calls for cleaning the bottom of the liner-piston rod chambers whenever the liner coolant reservoir is serviced. It explains that these chambers collect coolant and mud passing the piston, directing the liquid to a drain line or the reservoir.
The passage warns that neglected deposits can contaminate coolant in a recirculating system. Continued mud accumulation can eventually allow contamination to reach the power end through extension-rod wipers or their housing gaskets. This describes a potential contamination route; it does not diagnose a specific leak from a photograph.
Record the chamber, not just the pump
The following editorial fields make the service record traceable; they are not additional OEM requirements:
- Equipment tag, model, serial number and applicable maintenance document.
- Coolant reservoir service work-order reference and date.
- Chamber identifier using the site's numbering and viewing-direction convention.
- Visible deposits before work, with their location; distinguish an observation from an assumed source.
- Cleaning actually completed under the approved procedure and the area it covered.
- Condition observed afterward, including visible residue or areas not checked.
- Photograph references where safe and permitted, responsible personnel, and unresolved follow-up items.
Use one entry per identified chamber. A statement such as “reservoir serviced” should not be copied into every chamber's cleanliness field. If an area could not be inspected, record that limitation instead of marking it clean.
Preserve three separate conclusions
“Deposits observed,” “cleaning completed” and “condition accepted” mean different things. A work record may establish the first two without establishing the third. Retain the applicable acceptance procedure and the authorized person's disposition rather than treating a before-and-after photograph as approval.
For suspected abnormal contamination, record the finding and refer it through the maintenance process. Do not infer from appearance alone that a piston, wiper or gasket has failed. Similarly, a visibly clean chamber does not verify coolant quality, drain performance or the condition of the power-end lubricant. Those checks require their own evidence and applicable instructions.
Keep related tasks distinct
The rod-wiper inspection record addresses the sealing barrier, while the liner-spray inspection addresses coolant delivery. Link relevant findings to those records without marking either task complete on the strength of a chamber-cleaning entry.
NOV 12-P-160 and NOV 14-P-220 are equipment navigation links, not proof of identical coolant routing or interchangeable components.
Physical work requires authorized personnel and the installed equipment's approved shutdown, energy-isolation, pressure-release and safe-access requirements. Follow applicable waste-handling requirements. This guide specifies no cleaning chemical, flushing method, contamination threshold or return-to-service decision.
Source and limits
NOV, How to Treat Your Type P Triplex Mud Pump, document 25-101131, page 15, Rod Chamber Cleanliness; checked 7 October 2026, Los Angeles time. The maintenance linkage and contamination route come from that passage. The checklist and distinctions between recorded work and acceptance are editorial suggestions. No service-life, stock or delivery claim is made.
FAQ
When does the cited passage call for rod-chamber cleaning?
It associates cleaning the chamber bottoms with each service of the liner coolant reservoir; use the applicable instructions for the installed equipment.
Does servicing the reservoir prove the chambers are clean?
No. The work record should identify the chambers and the condition actually observed in each.
Does visible mud establish a failed wiper?
No. Record the observation and seek the appropriate assessment; the source's possible contamination route is not a component diagnosis.
Can a clean photograph authorize restarting the pump?
No. A photograph documents a visible condition only; applicable acceptance checks and return-to-service authorization remain separate.