Why We Built the PM Scheduler as a Nightly Job, Not a Calendar
Most CMMS products let you set recurring calendar events for PMs. We built a nightly scheduler that re-evaluates every asset every night. Here's why that distinction matters at scale.
When we designed the PM scheduler, the obvious approach was a calendar. Set a recurring event ("HVAC filter check every 90 days") and generate a work order on the due date. Every CMMS in the market does this. We decided not to.
The reason is that calendar-based PMs optimize for schedule adherence, not asset reliability. Those are different things, and the difference compounds at scale.
What a calendar-based PM system gets wrong
A calendar PM fires on a fixed date regardless of context. It does not know that the HVAC unit ran continuously at 105% capacity for the last 30 days. It does not know that the unit was serviced six weeks ago during an emergency repair and the filter was replaced then. It just fires on schedule.
The result is one of two failure modes: PMs that are too late, or PMs that are wasteful. Across 2,000 assets, this is a significant misallocation of technician time.
How the nightly job works
Arckium runs a scheduler every night at 02:00 that evaluates every asset in the system against a set of conditions. For each asset, it checks:
- Days since last PM of each type (interval-based)
- Days since last emergency or corrective work order on this asset (recent work modifier)
- Asset operational load data if IoT-connected (usage hours, cycle count)
- Open work orders that would conflict with a scheduled PM (collision avoidance)
- Upcoming occupancy peaks or operational constraints (schedule awareness)
Based on these inputs, the nightly job decides: does this asset need a PM work order generated for tomorrow?
Why this matters at scale
For 500 assets, the nightly job might produce 15 PMs on a given day where the calendar would have produced 22, 7 of which would have been premature or redundant given recent corrective work. That is 7 fewer technician-hours spent on unnecessary PMs.
A concrete example
Hotel HVAC filter check: 90-day interval. Calendar system generates the work order on day 90 regardless of context. Nightly job on day 71 detects that this unit had a refrigerant leak repaired on day 58, during which the filter was replaced. It recalculates the next PM due date from day 58, suppresses the day-90 work order. The technician is not sent to do unnecessary work. The asset record accurately reflects the actual service date.
The PM schedule is not a calendar. It is a living assessment of what each asset actually needs, updated every night.
The trade-off
The nightly job model requires more upfront configuration: every asset needs a PM policy with rules, not just a calendar entry. It also requires that corrective work orders accurately document what was serviced. The payoff is a PM programme that gets smarter over time rather than one that mechanically fires on schedule.
For facilities running more than 200 assets, the investment in setup pays back in the first quarter.