What engine does the Cummins C250 D6 use?

The Cummins 250 kW diesel generator (model DQDAA) uses the QSL9-G7, an 8.8-liter, inline-6-cylinder, turbocharged and charge-air-cooled diesel rated at 1800 rpm. EPA Tier 3 certified. The QSL9 features Bosch high-pressure common rail (HPCR) fuel injection, a Holset HX40 wastegated turbocharger, a 24-valve cylinder head, and integrated fluid circuits that replace external hoses.

What are the standby and prime ratings of the C250 D6?

Standby rating is 250 kW (313 kVA) at 60 Hz, 0.8 power factor. Prime rating is 225 kW (281 kVA). Both at 1800 rpm. A DCC (data center continuous) rating of 410 kW (513 kVA) is also available.

What is the model designation for the 250 kW Cummins diesel generator?

The 250 kW standby diesel generator is designated DQDAA in the Cummins North American product line. It uses the QSL9-G7 engine with an HCI434F alternator and PowerCommand 2.3 control system.

What are the service intervals for the C250 D6?

Oil and filter changes are due at 500 hours or 12 months, whichever comes first. Air filter and fuel filter replacement at 500-hour intervals. Coolant flush at 4,000 hours. Major overhaul interval is 25,000 hours under standard standby duty conditions.

How does the C250 D6 compare to the C275 D6?

Both models use the same QSL9-G7 engine block and HCI434F alternator. The C275 (DQDAB) is calibrated for 275 kW standby vs 250 kW for the C250 (DQDAA). Fuel consumption is proportionally higher on the C275. If your peak load is under 250 kW, the DQDAA provides a more conservative engine loading.

Can {company} service the C250 D6 in Northern California?

Yes. OnPoint Generators serves the San Francisco Bay Area, Silicon Valley, and broader Northern California with authorized Cummins service. We carry QSL9 parts, InPower diagnostic tooling, and provide annual maintenance, load bank testing, and emergency response for 250 kW installations.

Cummins · Cummins D6 Commercial Diesel

Cummins C250 D6

Name: Cummins C250 D6
Brand: Cummins
SKU: c250-d6

250 kW standby / 225 kW prime · Diesel · Liquid-cooled

250 kW EPA Tier 3 diesel standby generator with Cummins QSL9-G7 inline-6 engine and PowerCommand 2.3 control. HPCR fuel system, sound-attenuated enclosure, for commercial and industrial standby applications.

Standby power: 250 kW / 225 kW prime
Voltage options: 120/208V, 277/480V, 347/600V
Frequency / Phase: 60 Hz · 3-phase
Engine: Cummins QSL9-G7 · 8.8L
EPA / Emissions: Tier 3

Commerciallight-industrialData Centers

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Overview#

The Cummins C250 D6 (model designation DQDAA) is a 250 kW standby diesel generator set built on the QSL9-G7 engine -- an 8.8-liter, inline-6-cylinder turbocharged and charge-air-cooled industrial diesel running at 1800 rpm. Rated at 313 kVA standby and 281 kVA prime at 60 Hz, the DQDAA is the entry point into the QSL9 engine family for Cummins commercial diesel generators. It also carries a DCC (data center continuous) rating of 410 kW / 513 kVA.

Standard equipment includes the PowerCommand 2.3 control with AmpSentry protective relay, PCCNet RS485 network interface, and a 320x240 graphic display. The engine features Bosch high-pressure common rail (HPCR) fuel injection, a Holset HX40 wastegated turbocharger, and a 24-valve cylinder head with four valves per cylinder for improved fuel efficiency and transient response. The unit is EPA Tier 3 certified and supplied with a sound-attenuated enclosure.

The DQDAA is designed for large commercial standby applications including hospitals, data centers, office towers, and industrial facilities where loads exceed the 200 kW capacity of the QSB7-based units.

Our Service Experience#

The QSL9-G7 is a robust engine platform with excellent field reliability. The HPCR fuel injection system is the most critical maintenance item -- fuel quality directly affects injector life. We recommend fuel polishing and regular water separator service on all QSL9-based installations. The Holset HX40 turbocharger is reliable but should be checked annually for shaft play and oil seal condition. The PowerCommand 2.3 control with AmpSentry provides comprehensive load protection, but trip curves should be verified against the actual connected load profile during commissioning.

Frequently Asked Questions#

What fuel consumption should I expect from the DQDAA? Based on the QSL9-G7 engine spec sheet, standby fuel consumption at full 250 kW load is approximately 19.5 gallons per hour. At 50% load, consumption drops to approximately 10.8 gallons per hour. These are engine-level figures; actual genset consumption may vary slightly.

Can the C250 D6 be paralleled? Yes. The PowerCommand 2.3 control supports paralleling with synchronizer and isochronous load sharing. Contact your Cummins distributor for multi-unit paralleling configurations.

Engineering specifications

Physical

Length: 150 in
Width: 56 in
Height: 72 in
Dry weight: 5,500 lb

Fuel system & runtime

Fuel use @ full load: 19.5 GPH
Fuel use @ 50% load: 10.8 GPH

Documents & downloads

Spec sheets & manuals

Spec sheet (datasheet)

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Estimate runtime for the Cummins C250 D6

Adjust load percent and tank size to estimate runtime. Pre-filled with this model's spec where available.

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Generator size

Fuel

Fuel tank capacity

gal

Load

Override full-load GPH (optional)

GPH

Estimated runtime

13.3 hours(0.6 days)

Fuel consumption ≈ 15.04 GPH at 75% load. Estimate based on industry-typical 1800 RPM standby curves (≈0.07 GPH/kW at full load). Actual consumption varies by engine, ambient temperature, fuel quality, and tuning.

Service intervals

Manufacturer-recommended intervals for the Cummins C250 D6 under standby duty. Field intervals may differ based on load profile, ambient conditions, and fuel quality.

Oil & filter: Every 500 hours or 12 months
Air filter: Every 500 hours
Fuel filter: Every 500 hours
Major overhaul: ≈ 25,000 hours

Common failure modes

What we've seen fail on this platform. Use as a service-planning reference, not a diagnostic — actual failure modes depend heavily on duty cycle and maintenance history.

Component	Symptom	Typical hours	Severity
HPCR fuel injection system	Injector fault codes, rough running, power loss, fuel in oil	—	severe
Fleetguard fuel filter assembly	Filter clogging, restricted fuel flow, hard start under load	—	moderate
Charge air cooler	Coolant in intake, white smoke, power loss on high-load events	—	severe
PowerCommand 2.3 AmpSentry relay	Nuisance overcurrent trips during motor-starting events	—	moderate

Frequently Asked Questions

What engine does the Cummins C250 D6 use?: The Cummins 250 kW diesel generator (model DQDAA) uses the QSL9-G7, an 8.8-liter, inline-6-cylinder, turbocharged and charge-air-cooled diesel rated at 1800 rpm. EPA Tier 3 certified. The QSL9 features Bosch high-pressure common rail (HPCR) fuel injection, a Holset HX40 wastegated turbocharger, a 24-valve cylinder head, and integrated fluid circuits that replace external hoses.
What are the standby and prime ratings of the C250 D6?: Standby rating is 250 kW (313 kVA) at 60 Hz, 0.8 power factor. Prime rating is 225 kW (281 kVA). Both at 1800 rpm. A DCC (data center continuous) rating of 410 kW (513 kVA) is also available.
What is the model designation for the 250 kW Cummins diesel generator?: The 250 kW standby diesel generator is designated DQDAA in the Cummins North American product line. It uses the QSL9-G7 engine with an HCI434F alternator and PowerCommand 2.3 control system.
What are the service intervals for the C250 D6?: Oil and filter changes are due at 500 hours or 12 months, whichever comes first. Air filter and fuel filter replacement at 500-hour intervals. Coolant flush at 4,000 hours. Major overhaul interval is 25,000 hours under standard standby duty conditions.
How does the C250 D6 compare to the C275 D6?: Both models use the same QSL9-G7 engine block and HCI434F alternator. The C275 (DQDAB) is calibrated for 275 kW standby vs 250 kW for the C250 (DQDAA). Fuel consumption is proportionally higher on the C275. If your peak load is under 250 kW, the DQDAA provides a more conservative engine loading.
Can OnPoint Generators service the C250 D6 in Northern California?: Yes. OnPoint Generators serves the San Francisco Bay Area, Silicon Valley, and broader Northern California with authorized Cummins service. We carry QSL9 parts, InPower diagnostic tooling, and provide annual maintenance, load bank testing, and emergency response for 250 kW installations.

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Transfer switches

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