Service parts for the DQCB
Grouped by system, with how many of each the parts manual calls for.
Air intake
1 requiredFuel system
1 requiredOil system
1 requiredElectrical
1 requiredPrices captured from merchant listings; some links are affiliate links. Confirm against your serial number before ordering.
Specifications
| Fuel | Diesel |
|---|---|
| Frequency | 60.0 Hz |
| Standby power | 750 kW |
| Standby kVA | 938 |
| Prime power | 680 kW |
| Emissions | EPA NSPS Stationary Emergency Tier 2 |
| Controller | PowerCommand, PowerCommand 2.3, PowerCommand 2100 |
| Oil capacity | 102.0 L |
| Alternator | Stamford/AvK HC634 (4-pole, Class F insulation) |
| Voltage options | 277/480 V |
| Phase | 3 |
| Rated current | 902 A |
| Power factor | 0.8 |
| Circuit breaker | 1200 A |
| Battery group | 4D |
| Battery cranking | 1600 amps minimum at ambient temperature of 0 °C to 10 °C CCA |
| Battery voltage | 24 volt, negative ground V |
| Battery quantity | 2 |
| Starting system | 24 V DC |
| Coolant capacity | 109.5 L |
| Max ambient | 50 °C |
| Dimensions (L×W×H) | 4395×1855×2065 mm |
| Dry weight | 6075 kg |
| Wet weight | 6337 kg |
| Sound level | 75.3 dBA @ 7 m |
| Fuel tank | 1500.0 L |
| Tank runtime | 29 hr |
Engine
| Oil capacity | 102.0 L |
|---|---|
| Coolant capacity | 109.5 L |
| Displacement | 23.15 L |
| Aspiration | Turbocharged and low temperature after-cooled |
| Rated speed | 1800 rpm |
Filters for the Cummins/Onan QSK23-G7 NR2
2Engine-mounted filters the filter manufacturers list for this engine family. These come from the engine, not from this generator set’s own parts list, so confirm against your serial number before ordering.
| System | Filter | Description | Cross-references | |
|---|---|---|---|---|
| Fuel / water separator | P552006 | Fuel Filter, Water Separator Spin-On Twist&Drain | CUMMINS 3089916, CUMMINS 4095189, NAPA 3645, BALDWIN BF1262 | FridayParts $42.88 |
Listed for this engine in only one kind of machine, so they may depend on how the engine was installed:
| System | Filter | Description | Cross-references | |
|---|---|---|---|---|
| Oil filter | P551670 | Lube Filter, Spin-On Full Flow | CUMMINS 298670, CUMMINS 299670, NAPA 1970, CARBOCOL 0026 | FridayParts $26.68 |
Same engine, other brands
1 brandThe Cummins/Onan QSK23-G7 NR2 in this set also powers 2 generator sets sold under 1 other brand. Service parts and maintenance intervals for the engine are shared; enclosure, alternator, controller and ratings are not.
| Brand | Models |
|---|---|
| MQ Power | 800kW Containerized Diesel Generator Set, CG800C2 |
Maintenance & consumables
for the Cummins/Onan QSK23-G7 NR2| Item | Spec | Capacity | Part # | Interval | |
|---|---|---|---|---|---|
| Air filter | AF25544 | AF25544 | Amazon eBay $285.93 NAPA $391.96 | ||
| Fuel filter | (1) primary element AF25544; (1) secondary element AF25545, (2) Cummins Filtration FS1006 | — | 500 hr | ||
| Fuel filter | FS1006 | FS1006 | Amazon eBay $29.99 NAPA $90.16 | ||
| Oil filter | Cummins QuickServe® Commitment | LF9325 | 250 hr | Amazon eBay $127.04 KuduParts $74.00 FridayParts $75.99 | |
| Battery | 526−0112 | A048G602 | 500 hr | eBay | |
| Belt | Steel, flanged; Stainless steel flex, NPT | — | 15000 hr | ||
| Coolant | Antifreeze 50/50 (Ethylene glycol) | 109.5 | — | 24000 hr | |
| Coolant filter | Cummins Filtration WF2076 | — | 500 hr | ||
| Oil | Cummins QuickServe® Commitment | — | 250 hr | ||
| Spark plug | — | 500 hr |
Service specifications
34| Type | Item | Value | Unit | Condition |
|---|---|---|---|---|
| Other | AC waveform Total Harmonic Distortion (THDV) | < 5 no load to full linear load, < 3 for any single harmonic | % | |
| Other | Compression ratio | 16:1 | ||
| Other | Telephone Harmonic Factor (THF) | < 3 | % | |
| Other | Telephone Influence Factor (TIF) | < 50 | per NEMA MG1-22.43 | |
| Pressure | BMEP at set rated load | 2214 | kPa | prime rating |
| Pressure | BMEP at set rated load | 2435 | kPa | standby rating |
| Pressure | Maximum back pressure | 10.1 | kPa | |
| Pressure | Maximum fuel inlet restriction | 13.44 | kPa | |
| Speed | Droop electronic speed governing | 0 to 10 | % | no load to full load |
| Speed | Frequency drift | +/-0.5 | % | 33 °C (60 °F) change in ambient temperature over an 8 hour period |
| Speed | Frequency regulation | Isochronous | ||
| Speed | Governor regulation class | Class G3 | ISO 8528 Part 1 | |
| Speed | Isochronous governing steady state accuracy | +/-0.25 | % | any steady state load from no load to full load |
| Speed | Over frequency shutdown/warning (81 o) default | 6 | Hz | 20 seconds, disabled |
| Speed | Overspeed limit | 2100 | rpm | |
| Speed | Random frequency variation | + 0.25 | % | |
| Speed | Random frequency variation | ± 0.25% | % | |
| Speed | Under frequency shutdown (81 u) default | 6 | Hz | 10 seconds |
| Temperature | Ambient design (standard set-mounted radiator cooling) | 50 | °C | |
| Temperature | Control operating ambient temperature | -40 to +70 | °C | |
| Temperature | Exhaust temperature | 458 | °C | prime rating, at set rated load |
| Temperature | Exhaust temperature | 476 | °C | standby rating, at set rated load |
| Temperature | HMI operating ambient temperature | -20 to +70 | °C | |
| Temperature | Maximum fuel inlet temperature | 71 | °C | |
| Voltage | Digital output voltage regulation | +/-1.0 | % | any loads between no load and full load |
| Voltage | Droop voltage regulation | 0-10 | % | no load to full load |
| Voltage | High AC voltage shutdown (59) default | 110 | % | 10 seconds |
| Voltage | Low AC voltage shutdown (27) default | 85 | % | 10 seconds |
| Voltage | Random voltage variation | + 0.5 | % | |
| Voltage | Random voltage variation | ± 0.5% | % | |
| Voltage | Voltage drift | +/-1.5 | % | 40 ºC (104 ºF) change in temperature in an eight hour period |
| Voltage | Voltage overshoot on engine starting or sudden load acceptance | 5 | % | maximum overshoot over nominal level |
| Voltage | Voltage regulation, no load to full load | + 0.5 | % | |
| Voltage | Voltage regulation, no load to full load | ± 0.5% | % | no load to full load |
Extracted from the manufacturer documentation linked to this model. Values are copied as printed; confirm against your unit's manual and serial number.
Recommended fluids
| Fluid | Grade | Standard | Ambient | Capacity | Notes |
|---|---|---|---|---|---|
| Fuel | number 2 diesel fuel | Direct injection, fuel filter, automatic electric fuel shutoff |
Extracted from the manufacturer documentation linked to this model. Values are copied as printed; confirm against your unit's manual and serial number.
Fault codes
5| Code | Name | Meaning | Severity | Action |
|---|---|---|---|---|
| 27 | Low AC voltage shutdown | Voltage on any phase has dropped below a preset value. Adjustable over a range of 50-95% of reference voltage, time delay 2-20 seconds. Default value is 85% for 10 seconds. | Shutdown | |
| 32 | Reverse power shutdown | Adjustment range: 5-20% of standby kW rating, delay 1-15 seconds. Default: 10%, 3 seconds. | Shutdown | |
| 59 | High AC voltage shutdown | Output voltage on any phase exceeds preset values. Time to trip inversely proportional to amount above threshold. Values adjustable from 105-125% of nominal voltage, with time delay adjustable from 0.1-10 seconds. Default value is 110% for 10 seconds. | Shutdown | |
| 81 o | Over frequency shutdown/warning | Generator set is operating at a potentially damaging frequency level. Settings adjustable from 2-10 Hz above nominal governor set point for a 1-20 second time delay. Default: 6 Hz, 20 seconds, disabled. | Warning | |
| 81 u | Under frequency shutdown | Generator set output frequency cannot be maintained. Settings adjustable from 2-10 Hz below reference governor set point, for a 5-20 second time delay. Default: 6 Hz, 10 seconds. | Shutdown |
Extracted from the manufacturer documentation linked to this model. Values are copied as printed; confirm against your unit's manual and serial number.
Procedures
1Generator Check List maintenance
- Check coolant level and record freeze protection: -45.
- Visually inspect radiator.
- Visually inspect radiator hoses.
- Check condition of coolant hoses.
- Check condition of fuel hoses.
- Check condition of engine belts.
- Record batteries and quantity: 2 4D.
- Record battery install date if applicable: 2023.
- Verify genset has battery charger.
- Verify genset has coolant heater.
- Check engine oil level.
- Record engine oil filters last changed date and hours: 414, 4/10/25.
- Inspect exhaust system for cracks/leaks.
- Check rain cap for proper operation.
- Verify generator end is 12 lead reconnectable and has PMG permanent magnet generator.
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 | Wye | 12/6 | Winding 311/312; ADS-631; feature code BC38-2 |
| 120/240 | 3 | Delta | 12/6 | Winding 311/312 |
| 127/220 | 3 | Wye | 12/6 | Winding 311/312 |
| 133/230 | 3 | Wye | 12/6 | Winding 311/312 |
| 139/240 | 3 | Wye | 12/6 | Winding 311/312 |
| 190/380 | 3 | Wye | Winding 311; ADS-631; feature code BC37-2 | |
| 200/400 | 3 | Wye | Winding 311; ADS-310; feature code BC35-2 | |
| 208/416 | 3 | Wye | Winding 311; ADS-632; feature code BC44-2 | |
| 240/416 | 3 | Wye | 12/6 | Winding 311/312 |
| 254/440 | 3 | Wye | 12/6 | Winding 311/312 |
| 266/460 | 3 | Wye | 12/6 | Winding 311/312 |
| 277/480 | 3 | Wye | 4 Wire | Voltage-277/480, 3 Phase, Wye, 4 Wire |
| 280/416 | 3 | Wye | Winding 311; ADS-632; feature code B733-2 | |
| 347/600 | 3 | Wye | 6 | Winding 07; ADS-309; feature code B720-2 |
| 380 | 3 | Wye | Winding 311; ADS-632; feature code BC43-2 | |
| 400 | 3 | Wye | Winding 312; ADS-310; feature code BC36-2 |
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 DQCB?
The Cummins/Onan DQCB is rated 750 kW standby (938.0 kVA).
What engine is in the Cummins/Onan DQCB?
The Cummins/Onan DQCB is powered by the Cummins/Onan QSK23-G7 NR2 engine.
What kind of fuel does the Cummins/Onan DQCB run on?
The Cummins/Onan DQCB runs on Diesel.
What's the oil capacity on a Cummins/Onan DQCB?
The Cummins/Onan QSK23-G7 NR2 engine in the Cummins/Onan DQCB has an oil capacity of 102.0 liters.
What is the coolant capacity of the Cummins/Onan DQCB?
The Cummins/Onan DQCB cooling system holds 109.5 liters (28.9 US gallons) for the radiator system including the engine, per the manufacturer specification sheet.
What is the continuous rating of the Cummins/Onan DQCB?
The Cummins/Onan DQCB is rated 680 kW prime (850 kVA), against 750 kW standby.
How loud is the Cummins/Onan DQCB?
The Cummins/Onan DQCB is rated at 75.3 dBA at 7 m, per the manufacturer specification sheet.
How much does the Cummins/Onan DQCB weigh?
The Cummins/Onan DQCB has a dry weight of 6075 kg (13393 lb).
How big is the fuel tank on the Cummins/Onan DQCB?
The Cummins/Onan DQCB has a 1500 liter (396 US gallon) fuel tank, giving about 29 hours of runtime.
What voltages is the Cummins/Onan DQCB available in?
The Cummins/Onan DQCB is offered in 277/480 V, 3-phase.
What battery does the Cummins/Onan DQCB use?
The Cummins/Onan DQCB uses 2 batteryies, 24 volt, negative ground V each, 1600 amps minimum at ambient temperature of 0 °C to 10 °C CCA, group 4D, per the manufacturer specification sheet. The starting system is 24 V DC.
What alternator does the Cummins/Onan DQCB use?
The Cummins/Onan DQCB uses a Stamford/AvK HC634 alternator. It has 4 poles. Insulation class F.
Which oil filter part number does the Cummins/Onan DQCB take?
The Cummins/Onan DQCB uses oil filter part number LF9325.
What fuel filter does the Cummins/Onan DQCB use?
The Cummins/Onan DQCB uses fuel filter part number FS1006.
What air filter does the Cummins/Onan DQCB use?
The Cummins/Onan DQCB uses air filter part number AF25544.
Troubleshooting
6Symptoms & remedies
| Symptom | Remedy |
|---|---|
| Battle Short Mode | If a bypassed shutdown fault occurs, the fault code and description will still be annunciated, but the genset will not shutdown. This will be followed by a fail to shutdown fault. |
| Derate | The derate function reduces output power of the genset in response to a fault condition. If a derate command occurs while operating on an isolated bus, the control will issue commands to reduce the load on the genset via contact closures or modbus. |
| Emergency Stop | Annunciated whenever either emergency stop signal is received from external switch. |
| Full Authority Electronic Engine Protection | Engine fault detection is handled inside the engine ECM. Fault information is communicated via the SAE-J1939 data link for annunciation in the HMI. |
| Low and high battery voltage warning | Indicates status of battery charging system (failure) by continuously monitoring battery voltage. |
| Weak battery warning | The control system will test the battery each time the generator set is signaled to start and indicate a warning if the battery indicates impending failure. |
Fault codes and symptom→remedy steps extracted from this model’s service/owner documentation; verify against the official manual before servicing. Full Cummins/Onan DQCB troubleshooting guide (71 entries) →
Repair guides
1Step-by-step procedures compiled from the Cummins/Onan service manual for this model.
Parts
14| Part # | Description | Qty | System | |
|---|---|---|---|---|
| 501-0876 | Line, Fuel Cooler Return (Bearward Cooling System, not shown) | 1 | Hose | Amazon eBay |
| 501-0877 | Line, Fuel Supply (Engine Accessories group) | 1 | Hose | Amazon eBay |
| 501-0892 | Line, Fuel Cooler Supply (Bearward Cooling System, not shown) | 1 | Hose | Amazon eBay |
| 503-1675 | Hose, Reducer (Air Cleaner group) | 1 | Hose | Amazon eBay |
| 503-2754-01 | Hose, Oil | 1 | Hose | Amazon eBay |
| A053A190 | Hose, Oil (Valve group) | 1 | Hose | Amazon eBay |
| A055E534 | Switch, Level (low coolant level warning) | 1 | Sensor | Amazon eBay |
| A059Z452 | Seal, O Ring (Valve group) | 1 | Seal | Amazon eBay |
| AF2559300 | Air Cleaner replacement element (Nelson), for Air Cleaner Housing 140-3737 | 1 | Air filter | Amazon eBay |
| 140-1548 | Indicator, Service | 1 | Service part / kit | Amazon eBay $49.99 NAPA $32.16 |
| 204-009 | Acronyms and Abbreviations | Service part / kit | Amazon eBay | |
| 3822735 | Plastic bead blasting media | 1 | Service part / kit | Amazon eBay |
| 4021375 | QSK23 Troubleshooting and Repair Manual | 1 | Service part / kit | Amazon eBay |
| KS-E368R | Head Office | 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 |
|---|---|---|---|
| Prime | 138.2 | 36.5 | |
| Prime | 25% | 58.3 | 15.4 |
| Prime | 50% | 100.4 | 26.5 |
| Prime | 60% | 12.0 | 3.2 |
| Prime | 75% | 140.6 | 37.1 |
| Prime | 100% | 178.9 | 47.3 |
| Standby | 25% | 62.7 | 16.6 |
| Standby | 50% | 108.8 | 28.7 |
| Standby | 75% | 152.6 | 40.3 |
| Standby | 100% | 194.1 | 51.3 |
Available documents
This page was generated from the 9 manufacturer documents above by automated extraction; every figure shown is copied from one of them. How the data is compiled.