A pump that ran 18 hours a day for the last quarter and a near-identical pump that sat idle on standby should never be on the same maintenance interval — yet calendar-based PM treats them exactly the same. Runtime-based scheduling counts actual operating hours instead of days on the calendar, so a heavily loaded compressor gets serviced sooner and a standby fan that barely ran doesn't get torn down for no reason. For rotating equipment where wear tracks with hours run, not days elapsed, this single change closes the biggest gap between maintenance effort and actual equipment need. Sign up free on OxMaint to start scheduling PM by runtime hours instead of the calendar.
PREVENTIVE MAINTENANCE · ROTATING EQUIPMENT · RUNTIME SCHEDULING
Runtime-Based PM for Pumps, Fans and Compressors
Trigger maintenance from actual operating hours, not calendar days — so heavily run equipment gets serviced on time and standby equipment doesn't get torn down early.
Compressor C-204 runtime since last PM
1
4
8
2
HOURS
3-5x
runtime variance commonly seen between standby and continuously loaded units of the same asset class
25%
average reduction in unnecessary PM labor when standby equipment moves to runtime-based scheduling
0
missed high-usage intervals when runtime hours, not dates, control the work order trigger
Why Runtime Hours Matter More Than Calendar Days
Bearing wear, seal degradation, and lubricant breakdown in rotating equipment correlate with hours of operation, not days since the last PM. A calendar-based schedule built around a 90-day interval assumes every asset runs the same duty cycle — which is rarely true once standby units, seasonal loads, and redundant equipment enter the picture.
Calendar-Based PM
Same 90-day interval for every pump regardless of duty cycle
Standby units torn down on schedule even with near-zero run hours
Heavily loaded units can run past their real wear point undetected
Runtime-Based PM
Interval triggers off actual logged or metered operating hours
Standby units stay in service until they accumulate real wear
High-duty units get serviced on time, regardless of calendar date
How a Runtime Trigger Reaches the Work Order
The mechanism is straightforward — runtime hours accumulate against the asset, and once the count crosses the defined interval, a work order is generated automatically.
1
Hours Logged
Runtime is captured from a hour meter, motor controller, or manual shift log entry against the asset.
2
Hours Accumulate
Total runtime since the last completed PM is tracked continuously in the CMMS for each asset.
3
Interval Reached
Once accumulated hours cross the defined runtime interval, the asset is flagged as due.
4
Work Order Issued
A PM work order is generated automatically and the runtime counter resets once it's completed.
RUNTIME TRACKING · AUTO-GENERATED PM · ROTATING EQUIPMENT
Stop Servicing Equipment by the Calendar
OxMaint tracks runtime hours per asset and generates PM work orders the moment the real interval is reached — not when a date on the calendar happens to arrive.
Typical Runtime Intervals by Equipment Type
These intervals vary by manufacturer and duty severity, but they illustrate how runtime hours — not days — should drive the PM trigger for common rotating auxiliaries.
| Equipment |
PM Task |
Typical Runtime Interval |
| Centrifugal pumps |
Bearing lubrication and seal inspection |
2,000 - 4,000 hours |
| Industrial fans |
Belt tension check, bearing grease |
1,500 - 3,000 hours |
| Reciprocating compressors |
Valve inspection, oil analysis |
1,000 - 2,000 hours |
| Rotary screw compressors |
Oil and filter change |
4,000 - 8,000 hours |
Expert Perspective
CO
C. Osei — Rotating Equipment Reliability Lead
16 years, pump and compressor maintenance program design
The clearest sign a plant needs runtime-based PM is a standby pump getting torn down on the same 90-day cycle as the unit running continuously next to it. Once you start tracking actual hours, the difference in real wear between those two pumps becomes impossible to ignore.
LF
L. Fontaine — Maintenance Planning Manager
CMMS rollout lead, runtime and condition-based PM transitions
Switching to runtime hours doesn't require a sensor on every asset. We started with manual hour-meter readings logged during rounds, and that alone caught two compressors that were running well past their interval while the calendar still showed weeks of slack remaining.
Frequently Asked Questions
How is runtime-based PM different from condition-based PM?
Runtime-based PM triggers on accumulated operating hours, a single, predictable measure. Condition-based PM triggers on a sensor reading such as vibration or temperature crossing a threshold. Many rotating equipment programs use both together — runtime for routine servicing, condition triggers for early failure warning.
Sign up free on OxMaint to set up either trigger type.
Do we need an automated hour meter on every pump and fan?
No. Manual hour-meter readings logged during operator rounds work as a starting point, and many motor controllers already track runtime that can be logged into the CMMS. Automated metering adds accuracy and speed later, but isn't required to begin.
What happens to the runtime counter after a PM is completed?
The runtime counter resets to zero once the PM work order is closed, and accumulation begins again from that point. This keeps the interval accurate to time actually run since the last service, not since the asset was commissioned.
Can runtime-based and calendar-based PM run on the same asset together?
Yes, and it's common practice. A pump might have a runtime-triggered bearing service alongside an annual calendar-based inspection that's required regardless of hours run, such as a safety or regulatory check.
Book a demo to see how OxMaint manages both trigger types on one asset.
RUNTIME-BASED PM · ROTATING EQUIPMENT · CMMS
Match PM Effort to Actual Equipment Use
OxMaint tracks runtime hours for every pump, fan, and compressor and triggers PM work orders the moment the real interval is reached — no wasted labor, no missed high-usage assets.
