A standby generator needs three layers of care: quick checks every week, an oil and filter service roughly every 250 run hours, and a thorough inspection with a load test at least once a year. Skip those and the machine will usually still start next week. It will fail on the one day the grid is down and you need it most, because that is when a weak battery, stale fuel or a clogged filter finally shows itself.
The schedule at a glance
| When | What to do |
|---|---|
| Weekly | Start and run 15 to 30 minutes. Check oil level, coolant level, battery terminals, and look for leaks under the set. |
| Every 250 run hours | Change engine oil and oil filter. Replace fuel filter. Check air filter and clean or replace. |
| Every 500 run hours | All of the above, plus valve clearance check, belt inspection, coolant condition test. |
| Annually | Full inspection, battery load test, fuel tank drain check for water and sludge, and a supervised load bank test. |
Hours matter more than months. A generator backing up a factory through frequent outages reaches 250 hours quickly. A home standby set might take two years, but the oil still degrades and the fuel still ages, which is why the calendar sets a minimum of two services a year regardless.
Why fuel deserves special attention in Uganda
Diesel kept in a tank for months absorbs moisture and grows algae, especially through rainy seasons. Water and sludge settle at the bottom of the tank, exactly where the pickup pipe sits. If your generator hunts, smokes or dies under load after months of sitting, fuel is the first suspect. We cover the other likely culprits in our troubleshooting guide.
The weekly exercise run
- Keeps the battery charged. The charging alternator only works when the engine runs, and battery failure is the most common no-start cause.
- Circulates oil over seals and bearings so they do not dry out.
- Reveals faults early. A leak, a new noise or slow cranking spotted on a Tuesday test is a cheap repair. The same fault at 9 pm during an outage is not.
Keep a log, or ask your contractor for one
Every service should be recorded: date, run hours, what was replaced, what was measured. A log turns maintenance from a matter of memory into evidence, keeps warranties valid, and tells the next technician exactly where the machine stands. Our maintenance contracts include the log, genuine filters and scheduled visits, so the schedule above happens without anyone at your office needing to remember it. And if you suspect the unit was never sized correctly to begin with, start with our sizing guide.
Frequently asked questions
How often should a standby generator be serviced?
Follow run hours, not just the calendar: oil and filters roughly every 250 run hours, with a full inspection at least twice a year even if the unit barely ran. Weekly no-load starts keep the battery and fuel system healthy.
How long should a generator run each week if there is no outage?
Run it for 15 to 30 minutes weekly, ideally on load. Regular exercise keeps the battery charged, circulates oil and reveals problems while they are still cheap.
What is the most common cause of generator failure?
Battery failure and stale or contaminated fuel top the list. Both are caught by a basic weekly check, which is why skipping small maintenance causes most big breakdowns.
