Use case 03 · Post-maintenance faults

A pump that came back louder after a seal replacement

The pump went back into service after a routine seal replacement, and operators noticed it was louder at the coupling end. Valqor read the work order notes alongside the vibration and bearing temperature trends.

Illustrative example based on a common failure pattern
Equipment
P-118 process pump and motor
Symptom
Drive-end vibration up from 2.1 to 4.7 mm/s after maintenance
Data used
Historian: 5 tags over 60 days · Work order with technician notes · Alarm log · Shift logs
01 · The pattern

What the data shows

Vibration and drive-end bearing temperature both stepped up on the day of the restart and have been creeping higher since. Nothing changed in the process conditions.

P-118 drive-end vibration and bearing temperature, 60 daysDrive-end vibration (mm/s)DE bearing temperature (°C)Seal replacement
After maintenance0.0504.0658.080Jul 11Jul 23Aug 4Aug 16Aug 28Sep 8Warning 4.5 mm/s

A step change on the day of the seal replacement, then a slow climb.

02 · The sequence

Maintenance day and after, Aug 18

Historian readings, alarms, operator notes and work orders, lined up on one timeline.

  1. Work orderWO-6612 opened: replace mechanical seal on P-118.
  2. Work orderCoupling spacer removed for seal access.
  3. Work orderSeal fitted, coupling reinstalled. No alignment readings recorded.
  4. HistorianP-118 restarted. Drive-end vibration 4.7 mm/s, against 2.1 before.
  5. Operator log“P-118 louder than before at the coupling end.”
  6. AlarmVI-118 high vibration warning, 4.9 mm/s.
03 · The causes

Likely causes, tested against the evidence

Each candidate cause is checked against the records, with the evidence for and against it shown side by side.

Misalignment after the coupling was reinstalled

Supported

Evidence forThe step change lines up with the restart to the hour. Drive-end bearing temperature rose 8 °C at the same time. No alignment record exists.

Evidence againstNo vibration spectrum available yet to confirm a 1x/2x pattern.

Soft foot or loose baseplate bolts

Possible

Evidence forThe baseplate was disturbed during the job.

Evidence againstNo record of bolts being loosened in the work order.

New seal rubbing

Weak

Evidence forThe seal is new.

Evidence againstSeal flush pressure and temperature are normal, with no leakage reported.

04 · The outcome

Finding and recommended actions

An engineer reviews the finding and the linked records before any action is taken.

The fault started with the maintenance, not with the process. The most likely cause is misalignment when the coupling went back on, and nothing in the record shows the alignment was checked.

  • Run a laser alignment check and record the readings.
  • Take a vibration spectrum to confirm the 1x/2x pattern before and after correction.
  • Make alignment readings a required field on work orders that remove a coupling.
More use cases
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See the investigation 02 · Recurring alarms

A compressor high-vibration alarm that comes back every afternoon

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See the investigation 04 · Repeat failures

A bad actor pump that keeps eating mechanical seals

Five seals in two years, each lasting less than the one before. The pump was spending more time below minimum flow.

See the investigation

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