A commercial generator maintenance checklist covers six things: engine service (oil, filters and coolant), fuel, batteries, the automatic transfer switch, testing under load, and the records that prove it was done. NFPA-110 requires monthly exercising under load and annual full-capacity load bank testing for Level 1 systems. If your generator has not carried 30% of its rated load for at least 30 minutes a month, it does not meet NFPA-110.
On Every Scheduled Service Visit
Generators rarely fail without warning. They fail because the warning signs got missed. A scheduled visit is where those signs get caught. On each one, the checklist is:
- Standard service and oil change, on a documented schedule
- Filter, coolant and fuel system service
- Battery testing, electrolyte checks and replacement when a battery is weak
- Automatic transfer switch (ATS) testing and exercise
- Safety and function testing
- A fuel sample taken for a third-party lab
- Documentation of everything that was checked, found and fixed
This is the visit our generator maintenance plans are built around.
Every Month: Exercise the Generator Under Load
NFPA-110 requires monthly exercising under load. The test that matters is load: if your generator has not carried 30% of its rated load for at least 30 minutes a month, it does not actually meet NFPA-110, even if it starts and runs every week.
Many standby units never see that much load in a routine exercise, which is where the annual load bank test comes in.
Every Year: Full-Capacity Load Bank Test
For Level 1 systems, NFPA-110 requires annual full-capacity load bank testing, and for healthcare facilities it is not optional. A portable resistive load bank lets the generator carry its full rated capacity under controlled conditions.
A complete test steps the unit through 25%, 50%, 75% and 100% of nameplate and logs voltage, frequency, amperage and exhaust temperature along the way. We run both 2-hour and 4-hour load bank tests and deliver the compliance report within 5 business days.
Fuel: Test It Before It Fails You
The most common reason a generator fails to start in an emergency is not the generator. It is the fuel. Diesel degrades, water condenses and microbial growth happens in tanks that sit.
Put fuel on the checklist: a sample on scheduled visits, sent to a third-party lab, and fuel polishing on site when the results call for it. Polishing filters water, sediment and microbial contamination out of the stored diesel.
Before Winter and Before Hurricane Season
Two seasonal checks belong on every Texas facility’s list:
- Before the first hard freeze: battery testing, a fuel sample sent to the lab and polishing if needed, a transfer switch test, and a load bank test if one is coming due. Cold saps battery cranking power and untreated diesel can gel.
- Before hurricane season opens on June 1: a load bank test, a fuel sample and polishing, battery and transfer switch checks, and any repairs the testing turns up.
See North Texas generator service and Gulf Coast hurricane standby for how we handle each season.
Keep the Records Audit-Ready
Surveyors and insurers go by the records, not by memory. NFPA-99 applies specifically to healthcare facilities and adds documentation, testing frequency and reliability requirements on top of NFPA-110.
Every Paradise EPS service ends with audit-ready documentation, and we track your testing windows and let you know before they close. We also train in-house maintenance staff so your team can spot small issues early, between our visits.