A standby generator sitting in a plant room spends nearly all its life doing nothing, and that's exactly the problem. Fuel goes stale, batteries lose charge, and an automatic transfer switch that hasn't moved in weeks can seize without a single warning light to show for it. The weekly run test is the only thing standing between "should work" and actually knowing it will, the moment mains power drops on a dust extraction system or an emergency lighting circuit that can't afford to wait. Sign up to schedule every weekly run test and log voltage, frequency, and ATS results against target range automatically.
Why It Matters
A generator that fails to start when the grid goes down usually shows the warning signs long before that moment — a dead battery, clogged fuel line, or a control panel error that a weekly exercise run would have surfaced. In a plant with DSEAR-relevant zones and safety-critical systems on standby power, that gap between "should start" and "did start" is exactly what the weekly test closes.
Two Tests, Two Different Jobs
Weekly Run Test
A short exercise run, typically 10 to 20 minutes at no or light load, confirming the generator starts, reaches rated output, and every gauge and indicator reads correctly.
Monthly Load Test
A minimum 30-minute run at 30% or more of rated capacity, with the ATS simulating a real outage, confirming the system performs under actual demand.
The Weekly Run Test Checklist
Record engine run time before starting: the running-time meter total confirms whether the unit has run since the last exercise
Check fuel, oil, and coolant levels before start: confirming adequate supply and no visible sediment or contamination in the fuel
Start and verify voltage and frequency reach rated output: recorded within manufacturer specification before the ATS would transfer any load
Record oil pressure and coolant temperature once stabilised: against the OEM's documented normal range for the running unit
Verify ATS position and indicator: Auto-Off-Manual switch confirmed in Auto, source indicator showing the correct power source
Scan the control panel for alarms: low fuel, high coolant temperature, or low oil pressure warnings noted and investigated, not cleared and ignored
Log the result and flag exceptions: start time, readings, and any out-of-range value recorded and routed for correction before the next test
A Result Logged, Not Just A Run Completed
A weekly run without a recorded result proves nothing when an auditor or insurer asks for evidence. Oxmaint captures voltage, frequency, ATS status, and every exception item against each generator's own history. Sign up for a free trial to schedule your weekly test cycle, or book a demo to see it configured for your plant.
Why A No-Load Weekly Run Isn't Enough On Its Own
Running a generator repeatedly at no or light load without ever loading it properly lets unburned fuel build up in the engine, a condition known as wet stacking, which quietly reduces efficiency and can foul the exhaust system over time. This is exactly why the weekly test and the monthly load test exist as separate exercises rather than one being a substitute for the other. The weekly run confirms the generator starts and reads correctly; the monthly load test confirms it can actually carry real demand, and it's the load test that clears any fuel residue the weekly runs allowed to accumulate.
Target Ranges To Check Against
| Parameter |
What To Check |
Reference Point |
| Voltage |
Reaches rated output before ATS transfer |
Manufacturer nameplate specification |
| Frequency |
Stable within manufacturer range once running |
Manufacturer nameplate specification |
| Fuel level and quality |
Adequate supply, no visible sediment or water |
Site fuel management procedure |
| ATS position |
Auto-Off-Manual switch in Auto, correct source shown |
ATS control panel indicator |
Frequently Asked Questions
Q
How long should a weekly run test actually last?
A weekly exercise run is typically 10 to 20 minutes at no or light load, long enough to confirm the generator starts correctly and reaches rated voltage and frequency. It's not a substitute for the monthly load test, which requires a minimum 30 minutes under at least 30% of rated capacity.
Q
What should be done if a control panel shows a warning during the weekly run?
Any illuminated warning, whether low fuel, high coolant temperature, or low oil pressure, should be investigated and corrected, not simply cleared and left. Ignoring a fault code at the weekly stage is how a minor issue turns into a failure to start when the generator is actually needed.
Q
Does running the generator weekly at no load cause any problems of its own?
Yes, repeated no-load or light-load running without a proper load test can lead to wet stacking, where unburned fuel builds up in the engine. This is why the monthly load test at 30% or more of rated capacity is required alongside the weekly run, not as an optional extra.
Know Your Standby Power Will Work Before You Need It
Oxmaint schedules your weekly run tests and monthly load tests automatically, logs voltage, frequency, fuel, and ATS verification against target range, and flags exception items straight to a corrective work order. Sign up for a free trial to run it on your own generator fleet, or book a demo to see it configured for your plant.
