Diesel generators and DG sets are the last line of defence when grid power fails — yet most facility teams only discover maintenance gaps during an actual outage. OxMaint's preventive maintenance platform helps facility managers schedule, track, and document every generator inspection before critical power failure occurs. This checklist covers every system a facility generator depends on — from batteries and fuel to load testing and emergency readiness.
Checklist · Electrical & Power Systems · Facility Management
DG Set & Generator Maintenance Checklist
A complete preventive maintenance framework for facility backup power systems — structured for daily, weekly, monthly, and annual inspection cycles.
P1 Critical Asset
Covers all DG Set Systems
CMMS-Ready Workflow
67%
Generator failures preventable with PM
$85K
Avg cost of generator failure incident
48 hrs
Typical emergency repair lead time
30%
Facilities with outdated generator logs
Daily Inspection Checklist
| Item | Check Point | Acceptable Range | Action if Fail |
|---|---|---|---|
| Battery Voltage | Measure starter battery terminal voltage | 12.4V – 12.8V (12V system) | Charge / replace battery |
| Fuel Level | Inspect fuel tank gauge reading | Above 75% capacity | Refuel immediately |
| Oil Level | Check engine crankcase dipstick | Between MIN and MAX marks | Top up with correct grade |
| Coolant Level | Inspect radiator overflow reservoir | Between LOW and FULL marks | Top up with demineralised water |
| Control Panel Alarms | Scan all warning and fault indicators | No active alarms | Log fault code, raise work order |
| Exhaust Visual | Check exhaust outlet for unusual smoke | Light grey / clear exhaust | Black = over-fuelling, white = coolant leak |
Weekly Checklist
| Item | Check Point | Standard / Tolerance | Action if Fail |
|---|---|---|---|
| No-Load Test Run | Start DG, run 10–15 min at no load | Stable idle RPM, no fault alarms | Log anomaly, schedule inspection |
| Battery Charger | Verify trickle charger output current | Charger LED green, 13.5–13.8V float | Replace charger unit or fuse |
| Fuel Leaks | Visual inspection of fuel lines and fittings | No visible seepage or stains | Isolate and replace fitting |
| Earthing / Grounding | Check earth cable connection tightness | Resistance < 1 Ohm | Re-terminate and re-test |
| Belt Tension (V-belt) | Inspect alternator drive belt deflection | 10–15mm deflection at midpoint | Adjust tensioner or replace belt |
Automate this checklist inside OxMaint — assign, track, close
No spreadsheets. No missed inspections. Full audit trail.
Monthly Checklist
| Item | Check Point | Standard / Tolerance | Action if Fail |
|---|---|---|---|
| Load Bank Test | Apply 50–75% rated load for 30 minutes | Voltage ±5%, frequency ±3 Hz, stable temp | Investigate governor / AVR fault |
| Air Filter | Inspect and clean engine air filter element | No visible clogging or dust accumulation | Clean or replace element |
| Cooling System | Check radiator fins, hoses, thermostat | No blockage, hoses pliable, no leaks | Flush / replace coolant hoses |
| Oil Condition | Check oil colour and viscosity on dipstick | Amber–light brown, no milky appearance | Schedule oil change immediately |
| ATS Panel Test | Simulate mains failure, verify ATS switchover | Transfer in < 10 seconds | Recalibrate or replace ATS relay |
| Fuel Water Separator | Drain water accumulation from separator bowl | No visible water in separator | Drain, inspect for contamination |
Annual Inspection Checklist
01
Engine Oil & Filter Change
Full drain and refill with OEM-specified grade. Replace oil filter cartridge. Log oil sample for lab analysis — TBN, wear metals, viscosity index.
02
Fuel System Overhaul
Replace fuel filters (primary + secondary). Drain and clean fuel tank sludge. Inspect injectors for spray pattern and pressure — replace at 8,000 hrs or annual.
03
Battery Replacement
Starter batteries degrade regardless of use. Replace every 2 years or on annual conductance test failure. Never defer this — 30% of generator start failures are battery-related.
04
Full Load Bank Test
Run at 100% rated kVA for 2 hours minimum. Record voltage, frequency, exhaust temp, and oil pressure at 15-min intervals. Mandatory for warranty and insurance compliance.
05
Thermographic Inspection
IR scan of control panel, busbar connections, and cable terminations under load. Identify hot spots before insulation breakdown — most insurance policies now mandate annual thermography.
06
Compliance Documentation
Update maintenance log book, service records, test certificates, and authority compliance documents. File with your CMMS for instant retrieval during audits and renewals.
Failure Risk Heatmap — DG Set Systems
Relative failure probability by system when PM intervals are missed
Battery System
Fuel Contamination
Cooling System
ATS Transfer Relay
Engine Oil Breakdown
Alternator Winding
Critical
High
Medium
Low
OxMaint PM Automation — How It Works
1
Add Asset
Register your DG sets in OxMaint with make, model, kVA rating, and location. Import existing service history in minutes.
2
Set PM Schedule
Choose daily, weekly, monthly, and annual templates. OxMaint auto-generates work orders on schedule — no manual creation needed.
3
Technician Executes on Mobile
Field teams receive checklist tasks on mobile — mark items, log readings, attach photos, and close work orders from the generator room.
4
Compliance Dashboard
Managers view PM completion rates, overdue tasks, and compliance scores in real time — exportable for insurance and audit submission.
Expert Review
AV
Arun Varghese
Facility Operations Manager — 20 years, Critical Infrastructure & Commercial Real Estate
"The single biggest risk in facility generator management is the gap between scheduled PM and actual execution. Teams know what to do — but without a digital system tracking every check, items get skipped under pressure. OxMaint closes that gap completely. When we audited one client's generator logs, they had 40% PM completion — on paper it looked fully maintained. With OxMaint, nothing falls through the cracks, and compliance documentation is always audit-ready."
40% → 97% PM completion in 60 days
67% reduction in unplanned generator failures
Audit-ready logs exported in one click
Frequently Asked Questions
How often should a facility DG set be load-tested?
Most facility standards and insurance policies require a monthly no-load test run of 10–15 minutes and a full load bank test at 75–100% rated capacity at least quarterly or annually depending on criticality. Hospitals, data centres, and critical infrastructure facilities typically mandate monthly full-load testing. OxMaint auto-schedules all test frequencies and generates compliance certificates after each completed test.
What is the most common cause of generator failure during a power outage?
Battery failure accounts for approximately 30% of generator start failures during actual outages, followed by fuel contamination (water ingress or microbial growth in diesel), and ATS transfer relay faults. These three failure modes are entirely preventable with a structured PM programme. Most critical failures occur in facilities where generators sit idle for months without inspection — the very scenario a CMMS-driven checklist eliminates.
Can OxMaint manage multiple DG sets across multiple facilities?
Yes — OxMaint is built for multi-site facility portfolios. You can manage generators across dozens of buildings from a single dashboard, with site-specific PM schedules, technician assignments, and compliance tracking. Facility managers get a consolidated view of PM completion rates, upcoming tasks, and overdue items across all sites. Book a demo to see the multi-site module.
What documentation does OxMaint generate for generator compliance audits?
OxMaint generates comprehensive maintenance history reports, PM completion records, technician sign-off logs, load test certificates, and oil analysis tracking — all exportable as PDF or Excel. These documents meet the requirements of most building authority inspections, insurance renewals, ISO 41001 facility management audits, and fire authority compliance checks. Every maintenance action is timestamped and technician-attributed for full traceability.
Never miss a generator inspection again
OxMaint automates your entire DG set PM programme — schedule, assign, track, comply
