Specifications
| Fuel | NG/LP |
|---|---|
| Frequency | 60.0 Hz |
| Standby power | 25 kW |
| Standby kVA | 25 |
| Emissions | EPA Emergency Stationary |
| Controller | PowerCommand 1.1 |
| Alternator | CA Series (Class H insulation) |
| Voltage options | 120/240 V, 120/208 V |
| Phase | 1 or 3 |
| Rated current | 104.2 A |
| Circuit breaker | 150 A |
| Battery cranking | 550 CCA |
| Battery voltage | 12 V |
| Battery quantity | 1 |
| Max ambient | 40 °C |
| Dimensions (L×W×H) | 1829×864×1157 mm |
| Dry weight | 503 kg |
| Sound level | 64.0 dBA @ 7 m |
Engine
| Coolant capacity | 12.8 L |
|---|---|
| Displacement | 2.4 L |
| Aspiration | Naturally aspirated or turbocharged (varies by generator set model) |
| Rated speed | 1800 rpm |
Maintenance & consumables
for the Cummins/Onan QSJ2.4| Item | Spec | Capacity | Part # | Interval | |
|---|---|---|---|---|---|
| Fuel filter | Every 500 hours of operation or as needed, whichever comes first | — | 500 hr | ||
| Oil filter | Every 1000 hours of operation or as needed, whichever comes first | — | 1000 hr | ||
| Battery | As needed | — | |||
| Oil | 500 miles or 6 months, whichever comes first | — | 804 hr |
Service specifications
2| Type | Item | Value | Unit | Condition |
|---|---|---|---|---|
| Pressure | Fuel supply pressure - maximum | 3.5 | kPa | |
| Pressure | Fuel supply pressure - minimum | 1.5 | kPa |
Extracted from the manufacturer documentation linked to this model. Values are copied as printed; confirm against your unit's manual and serial number.
Voltage reconnection
| Voltage | Phase | Connection | Leads | Notes |
|---|---|---|---|---|
| 120/208 | 3 | 12-lead | 12 | |
| 120/240 | 1 | 4-lead | 4 | |
| 120/240 | 3 | 12-lead | 12 |
Extracted from the manufacturer documentation linked to this model. Values are copied as printed; confirm against your unit's manual and serial number.
Common questions
What size generator is the Cummins/Onan RS 25?
The Cummins/Onan RS 25 is rated 25 kW standby (25.0 kVA).
Which engine powers the Cummins/Onan RS 25?
The Cummins/Onan RS 25 is powered by the Cummins/Onan QSJ2.4 engine.
What kind of fuel does the Cummins/Onan RS 25 run on?
The Cummins/Onan RS 25 runs on NG/LP.
Which alternator is fitted to the Cummins/Onan RS 25?
The Cummins/Onan RS 25 uses a CA Series alternator. Insulation class H.
Parts
13| Part # | Description | Qty | System | |
|---|---|---|---|---|
| A046N983 | Preventive Maintenance Kit –Heavy Duty | 2 | Air filter | Amazon eBay |
| A046N985 | Preventive Maintenance Kit (Normal Duty Air Filter) | 2 | Air filter | Amazon eBay |
| A046N987 | Preventive Maintenance Kit (Normal Duty Air Filter) | 2 | Air filter | Amazon eBay |
| CA115-T12 | Large, Oil Cooler | Oil filter | Amazon eBay | |
| CA135-E12 | Large, Oil Cooler | Oil filter | Amazon eBay | |
| A046J612 | Base Barrier – Elevated Genset | 1 | Service part / kit | Amazon eBay |
| A046L270 | Instruction Sheet | 1 | Service part / kit | Amazon eBay |
| CA115-H14 | Small | Service part / kit | Amazon eBay | |
| CA115-J12 | Small | Service part / kit | Amazon eBay | |
| CA115-L14 | Small | Service part / kit | Amazon eBay | |
| CA115-M12 | Large | Service part / kit | Amazon eBay | |
| CA115-P12 | Large | Service part / kit | Amazon eBay | |
| CA115-R12 | Large | Service part / kit | Amazon eBay |
Service, wear & replacement parts referenced for this model and its engine — confirm the exact part for your serial number. See the full parts catalog to search and cross-reference.
Fuel consumption
| Rating | Load | L/h | gal/h |
|---|---|---|---|
| Standby | 25% | 5.3 | 1.4 |
| Standby | 50% | 7.95 | 2.1 |
| Standby | 75% | 10.6 | 2.8 |
| Standby | 100% | 13.25 | 3.5 |
Available documents
Spec sheet (Cummins/Onan)Spec sheet — NAS-5775-EN (Cummins/Onan)Reference (Cummins/Onan)