Generator Maintenance Checklist
Standby and emergency generators carry weekly visual and operational checks, a monthly load run, and annual service under NFPA 110 for Level 1 and Level 2 emergency power supply systems (EPSS), backed by EGSA preventive-maintenance practice. This checklist consolidates the engine, fuel, battery, cooling, exhaust, controls, and transfer-switch tasks into one record you can complete on site and keep on file for the owner and your AHJ. Print it as-is, or run the same items digitally in Forz, where technicians record Pass, Fail, or Bypass inspection results with photos on the iOS and Android apps, and recurring jobs auto-generate each weekly, monthly, and annual visit on schedule.
Generator Maintenance Checklist
Generator Services · Checklist
Company: ______________
Date: ______________
Technician: ______________
Unit & Site Information
- Customer / facility name and service contract number
- Site address and building or area served by the EPSS
- Generator make, model, and serial number
- Engine make, model, and serial number
- Nameplate rating — kW / kVA, voltage, phase, and frequency (Hz)
- Fuel type — diesel / natural gas / LP / bi-fuel
- EPSS classification — NFPA 110 Level 1 or Level 2; Type and Class
- Run-hour meter reading at start of visit
- Service interval covered — weekly / monthly / annual
- Technician name, EGSA / manufacturer certification number, and AHJ
Weekly Visual Inspection (engine off)
- Generator and enclosure clean, dry, and free of leaks, debris, and rodent damage
- Engine oil level at full mark on dipstick; no oil under engine
- Engine coolant level full at recovery bottle / radiator; no coolant under unit
- Fuel level adequate in main tank and day tank; record percentage or gallons
- No diesel fuel, coolant, or oil leaks at hoses, fittings, filters, or seals
- Belts and hoses free of cracks, glazing, fraying, and softness; tension correct
- Air filter restriction indicator within range; intake clear and unobstructed
- Battery charger powered and showing float / charging; DC voltage within range
- Block / coolant heater warm to touch and energized; jacket-water temperature adequate
- Controller in Auto / Ready; no active alarm, warning, or shutdown lamps
- Louvers, dampers, and ventilation openings clear and free to operate
Battery & Starting System
- Battery case free of cracks, swelling, corrosion, and electrolyte leakage
- Terminals clean, tight, and protected; cables free of fraying or chafing
- Electrolyte level above plates on serviceable batteries; top up with distilled water as needed
- Specific gravity per cell on flooded batteries (≈1.260 fully charged; recharge below ≈1.215)
- Open-circuit DC voltage recorded; AGM / sealed batteries tested by conductance
- Float / equalize voltage at charger output recorded and within manufacturer range
- Battery load test or conductance test result recorded; replace per age and capacity
- Cranking voltage observed during start; no excessive voltage dip
Engine, Lubrication & Cooling
- Oil pressure at idle and at rated speed recorded; within manufacturer range
- Coolant concentration tested — 50/50 antifreeze mix; freeze point and SCA / DCA level adequate
- Radiator core, fins, and air-cooled cylinders clean and unobstructed
- Water pump and fan free of leaks, play, and abnormal noise; fan guard secure
- Belt tension and alignment verified; record condition of each belt
- Engine governor / speed control and throttle linkage free and lubricated
- Oil, fuel, and coolant filter dates / hours noted; change per service interval
- Crankcase breather clear; no excessive blow-by observed
Fuel System (diesel and gaseous)
- Main tank and day-tank levels recorded; fuel-transfer pump and float controls operate
- Water drained from fuel-water separator / primary filter bowl; record water present yes / no
- Fuel-water separator and primary / secondary filter condition and change interval noted
- Diesel polishing / fuel-quality status noted; sample pulled where contract requires
- Day-tank overflow, rupture-basin, and leak-detection devices intact and functional
- Fuel lines, flex connectors, and fittings free of leaks and chafing
- Gaseous units — gas pressure at regulator within range; piping and joints leak-checked
- Tank vent, fill cap, and gauge operational; secondary containment dry
Exhaust, Air Intake & Enclosure
- Exhaust manifold, muffler, and piping free of leaks, cracks, and excessive soot
- Exhaust flex connector and supports intact; rain cap / discharge clear and operable
- Condensate drain on exhaust open and draining; no water trapped in muffler
- Air intake hoses, clamps, and turbo connections tight; no leaks downstream of filter
- Enclosure / room ventilation, intake and discharge louvers, and dampers operate freely
- Combustion-air and cooling-air paths unobstructed; ambient temperature acceptable
- No signs of wet stacking (unburned fuel / oily residue) at exhaust outlet
Controls, Alarms & Transfer Switch (ATS)
- Controller display, gauges, and indicating lamps tested and reading normally
- Remote annunciator and trouble alarms verified; signals reach the monitored point
- Emergency-stop function tested and confirmed operational (per site procedure)
- Engine safety shutdowns verified per service interval — low oil pressure, high coolant temperature, overspeed, overcrank
- ATS cabinet, contacts, and connections inspected; no overheating, arcing, or loose lugs
- Time-delay settings (engine start, transfer, retransfer, cooldown) recorded
- EPSS breakers between EPS and ATS load terminals exercised with EPS off — typically on an annual basis per the adopted edition
Operational & Load Run Test
- Crank / start initiated; time to start and time to reach rated voltage and frequency recorded
- Voltage (per phase), frequency (Hz), and engine RPM at no load recorded
- ATS exercised — primary to alternate and back to primary; transfer and retransfer confirmed
- Monthly load run — commonly cited as at least 30 minutes at roughly 30% of nameplate kW, or to the manufacturer's minimum exhaust-gas temperature; confirm duration and load against the adopted NFPA 110 edition
- Under load — kW output, per-phase amperage, voltage, frequency, and power factor recorded
- Under load — oil pressure, coolant temperature, fuel pressure, and exhaust temperature recorded
- Annual supplemental load-bank run for units that do not reach monthly load (commonly cited 50% nameplate for 30 min plus 75% for 1 hr) — verify edition and AHJ
- Cooldown completed and unit returned to Auto / Ready; run-hour meter reading at end of visit
Results & Sign-Off
- Overall result — satisfactory / deficiencies noted / out of service
- Deficiencies described with severity, affected component, and code or manufacturer reference
- Parts replaced and consumables used (oil, filters, coolant, belts) with quantities
- Corrective action recommended and work order or proposal reference
- Photos and meter readings attached (count and reference)
- Owner or representative notified of deficiencies — name and date
- Technician signature, certification number, and date
- Owner / representative signature and date
Technician signature
Customer / owner signature
Tasks above are summarized from publicly available NFPA 110 and EGSA preventive-maintenance guidance as of 2026 and generally apply to Level 1 and Level 2 emergency power supply systems; intervals, load percentages, and exhaust-gas-temperature methods are edition-dependent. NFPA 110 editions and locally adopted amendments vary; verify the scope, frequencies, and load-test requirements with your AHJ and the adopted edition, and follow the engine and generator manufacturer's service intervals. This template is a starting point for your maintenance records — it is not the standard, and it does not replace inspection, testing, and service by qualified personnel.
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