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Cummins/Onan C22 N6 Generator Set

The Cummins/Onan C22 N6 is a 22 kW (22 kVA) natural gas or propane standby generator set powered by a Cummins/Onan QSJ2.4 engine. It is available at 120/240 V, 120/208 V and 277/480 V, single-phase and 60 Hz. It holds about 4.3 L (1.1 gal) of oil and 12.8 L (3.4 gal) of coolant. Starting uses group-26 battery rated 545 CCA at 12 V. The set measures 1830×864×1152 mm (72.0×34.0×45.4 in) and weighs about 1109 kg (2445 lb).

22 kW
Standby
2.4 L
Displacement
4.3 L
Oil capacity
5
Document types

How to read your Cummins/Onan serial & model number →

Typical fuel consumption for 20–25 kW Bi-Fuel (NG/LP) generators →

Compare with other 20–25 kW Bi-Fuel (NG/LP) generators →

Service parts for the C22 N6

Grouped by system, with how many of each the parts manual calls for.

Air intake

1 required

Oil system

1 required

Prices captured from merchant listings; some links are affiliate links. Confirm against your serial number before ordering.

Specifications

Fuelnatural gas or propane
Frequency60.0 Hz
Standby power22 kW
Standby kVA22
ControllerPowerCommand (HMI211 operator)
Oil capacity4.3 L
AlternatorBrushless, 2-pole rotating field, single bearing (2-pole)
Voltage options120/240 V, 120/208 V, 277/480 V
Phase1 or 3
Battery group['26 standard', '34 high capacity']
Battery cranking[545, 850] CCA
Battery voltage12 V
Starting system12 V DC
Dimensions (L×W×H)1830×864×1152 mm
Dry weight1109 kg

Engine

Cummins/Onan QSJ2.4
Coolant capacity12.8 L
Displacement2.4 L
AspirationNaturally aspirated or turbocharged (varies by generator set model)
Rated speed1800 rpm

Maintenance & consumables

for the Cummins/Onan QSJ2.4
ItemSpecCapacityPart #Interval
Air filterPreventive Maintenance Kit (Normal Duty Air Filter)A046N985 Amazon eBay
Fuel filterEvery 500 hours of operation or as needed, whichever comes first—500 hr
Oil filterLarge, Oil CoolerCA135-E12 Amazon eBay
BatteryAs needed—
Oil500 miles or 6 months, whichever comes first—804 hr

Service intervals

30
ItemActionHoursMonthsNotes
Air cleaner restriction indicator (where fitted)Check24 hrDaily or after 24 hours, whichever occurs first. If indicator shows red, replace air cleaner elements and reset indicator.
Air intake systemInspect24 hrDaily or after 24 hours. Visually and audibly check for leaks, wear or damage.
Batteries - connections secure and battery area clearCheck24 hrDaily or after 24 hours and Weekly or after 50 hours.
Coolant level of radiator(s) (water jacket & LTA)Check24 hrDaily or after 24 hours. Top up with Cummins recommended coolant mix if low.
Engine oil levelCheck24 hrDaily or after 24 hours. Top up to engine specifications level with recommended oil.
Exhaust components and hardware (fittings, clamps, fasteners)Inspect24 hrDaily or after 24 hours and Weekly or after 50 hours. Visually and audibly inspect for wear or damage.
Generator set enclosureCheck24 hrDaily or after 24 hours. Walk-around inspection; ensure no inlets/outlets restricted and safety systems in place.
Operator panelCheck24 hrDaily or after 24 hours. Replace component if not functioning properly.
Battery conditionCheck50 hrWeekly or after 50 hours.
Charge alternatorCheck50 hrWeekly or after 50 hours. Check visually and audibly when generator set is running.
Coolant lines and radiator hosesCheck50 hr12 moWeekly or after 50 hours and 12 Months or after 200 Hours. Check for leaks, wear and cracks.
Cooling fan bladesInspect50 hrWeekly or after 50 hours. Visually inspect for wear or damage.
Drive belt, condition and tensionCheck50 hrWeekly or after 50 hours. Check for wear or slippage.
Emergency Stop Button (where fitted)Test50 hrWeekly or after 50 hours. With generator set running, press Emergency Stop button.
Fuel lines and hosesCheck50 hrWeekly or after 50 hours. Visually check for leaks, wear or damage.
Radiator air flowInspect50 hrWeekly or after 50 hours. Check for blockage, debris, wear or damage.
Air cleanerReplace100 hrReplace air cleaner.
Aftercooler core (where fitted)Check200 hr12 mo12 Months or after 200 Hours.
Coolant heater (where fitted)Check200 hr12 mo12 Months or after 200 Hours. Check it has power and is running.
Electrical connections (battery, starter motor and alternator connections)Check200 hr12 mo12 Months or after 200 Hours.
Engine groundCheck200 hr12 mo12 Months or after 200 Hours. Clean as necessary.
Engine mountsCheck200 hr12 mo12 Months or after 200 Hours.
Engine oil and filtersReplace200 hr12 moFirst service — After the initial 50 hour interval and every 200 hours thereafter; 12 Months or after 200 Hours.
Radiator coreClean200 hr12 mo12 Months or after 200 Hours. Cleaning schedule may be reduced depending on operating conditions/environment.
Spark plugsInspect200 hr12 mo12 Months or after 200 Hours. Replace as necessary.
Starting motorCheck200 hr12 mo12 Months or after 200 Hours.
Timing belt conditionInspect200 hr12 mo12 Months or after 200 Hours. Visually inspect.
Turbocharger (where fitted)Check200 hr12 mo12 Months or after 200 Hours.
Water pumpCheck200 hr12 mo12 Months or after 200 Hours.
Cooling system coolantReplace24 mo2 Years.

Extracted from the manufacturer documentation linked to this model. Values are copied as printed; confirm against your unit's manual and serial number.

Service specifications

12
TypeItemValueUnitCondition
GapSpark plug gap (NA)0.040inch (1.0 mm)
GapSpark plug gap (T/TAA)0.030inch (0.76 mm)
OtherMaximum I2 (negative sequence)8%
PressureEngine oil pressure low (shutdown) threshold - Code 41526psig (180 kPa)for greater than 10 seconds
PressureFuel supply pressure - maximum3.5kPa
PressureFuel supply pressure - minimum1.5kPa
ResistanceEngine harness pin resistance (ECM to sensor) - Code 5569 diagnosis5 ohms or lessohms
SpeedEndurance run period (normal duty air cleaner test)30secondsafter oil/filter change, run then shut off and wait 5 minutes
TemperatureEngine coolant temperature above normal (warning) - Code 146225°F (107.2 °C)for greater than 5 seconds
TemperatureIntake manifold temperature high (shutdown) - Code 155203°F (95 °C)for greater than 10 seconds
TemperatureIntake manifold temperature high (warning) - Code 488185°F (85 °C)for more than 90 seconds
TorqueSpark plug torque15ft-lb (20 N-m)

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

FluidGradeStandardAmbientCapacityNotes
CoolantCummins recommended coolant mixTop up coolant system to specifications level with Cummins recommended coolant mix. For NFPA 110 applications a coolant heater is required.
Engine oil5W30 API SMAPI SM4.3 LApproximately 4.5 quarts (4.3 L). Dipstick High mark 4.3 L (4.5 qt), Low mark 3.8 L (4.0 qt).
FuelNatural gas or propane vaporFuel pressure 6-14 inch water column.

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

13
CodeNameMeaningSeverityAction
143Engine Oil Pressure LowEngine oil pressure is below the low oil pressure warning threshold.WarningCheck the oil level and add oil if necessary. Inspect the engine and surrounding area for external oil leaks; contact your local dealer if a leak is present.
1438Fail to CrankThe engine failed to crank after the generator control received a start signal.ShutdownVerify battery voltage is at least 12 VDC. Charge or replace the battery as necessary.
146Engine Coolant Temperature Above NormalEngine coolant temperature has exceeded 225 °F (107.2 °C) for greater than 5 seconds.WarningReduce loads or recirculation of discharge air in elevated ambient; inspect/clear enclosure air intake and discharge blockage; check and add coolant; clean the radiator core; inspect and replace a broken fan belt.
1472High AC CurrentThe generator output current has exceeded at least 150% of rated current.ShutdownReduce the generator set load by powering off unnecessary household appliances.
151Engine Coolant Temperature HighEngine coolant temperature has exceeded the alarm (shutdown) threshold for high coolant temperature.ShutdownReduce loads or recirculation of discharge air in elevated ambient; clear enclosure air intake and discharge blockage; check and add coolant; clean the radiator core; inspect and replace a broken fan belt.
155Intake Manifold Temperature HighEngine intake manifold temperature has exceeded 203 °F (95 °C) for greater than 10 seconds.ShutdownReduce loads or recirculation of discharge air in elevated ambient; clear enclosure air intake and discharge blockage; check and add coolant; clean the radiator core; inspect and replace a broken fan belt.
197Coolant Level LowCoolant level sensor signal is showing a low coolant level for greater than 10 seconds.WarningRemove radiator cap and check that coolant is up to the required level.
415Engine Oil Pressure LowEngine oil pressure is below 26 psig (180 kPa) for greater than 10 seconds.ShutdownCheck the oil level and add oil if necessary. Inspect the engine and surrounding area for external oil leaks; contact your local dealer if a leak is present.
421Engine Oil Temperature HighThe control has detected the engine oil temperature has exceeded the warning threshold.WarningReduce loads or recirculation of discharge air in elevated ambient; inspect/clear enclosure air intake blockage; check and add coolant.
441Battery Voltage LowBattery voltage low.WarningInspect the battery cable connections for corrosion and for loose connections.
488Intake Manifold Temperature HighEngine intake manifold temperature has exceeded 185 °F (85 °C) for more than 90 seconds.WarningReduce loads or recirculation of discharge air in elevated ambient; clear enclosure air intake and discharge blockage; check and add coolant; clean the radiator core; inspect and replace a broken fan belt.
5134Unknown Shutdown at IdleThe generator set failed to start.ShutdownCheck that the manual shutoff valves are open (fuel supply issue).
5569Engine CombustionRapid rate of increase of intake manifold temperature detected.ShutdownInspect hose couplings between compressor outlet and intake manifold; inspect the turbocharger; inspect the mixer; check the TMAP sensor value with GCP Display service tool or InPower; inspect the engine harness and connector pins (resistance should be 5 ohms or less) and repair or replace as necessary.

Extracted from the manufacturer documentation linked to this model. Values are copied as printed; confirm against your unit's manual and serial number.

Procedures

11
Check the fault log diagnostic
  1. From any Information Menu, hold down the up and down arrows simultaneously for two seconds to access the Service Menu.
  2. Select Fault History.
  3. Active faults are displayed first, followed by Fault History screens newest to oldest.
Adding oil maintenance

⚠ Too much oil can cause high oil consumption. Too little oil can cause severe engine damage.

⚠ Hot engines can burn you. Ensure that the generator set engine has cooled down before adding or draining the oil.

  1. Ensure that the oil fill cap area is clean, and prevent debris from entering the engine.
  2. Add the appropriate amount of oil, based on the engine oil level check performed beforehand.
  3. Recheck the engine oil level. Based on the results, add or drain oil.
  4. Clean up and dispose of any oil in accordance with local/state regulations.
Air cleaner element removal and installation (Heavy Duty) maintenance
  1. Wipe dirt from the cover and upper portion of the air cleaner.
  2. Lift tab and turn end cover counter clockwise.
  3. Pull the end cover away from the housing.
  4. Remove the media from the housing.
  5. To install: insert the media into the housing, install the end cover onto the housing, turn clockwise until the latch snaps into place.
Air cleaner removal and installation (Normal Duty) maintenance

⚠ Holes, loose-end seals, dented sealing surfaces, corrosion of pipes render the air cleaner inoperative and require immediate element replacement.

  1. Loosen the strap clamp.
  2. Wipe away debris around the air cleaner connection to the engine.
  3. Remove the dirty cleaner and dispose of the dirty element per local requirements.
  4. To install: install the air cleaner and tighten the strap clamp.
Changing engine oil and oil filter maintenance

⚠ Used engine oil can be carcinogenic and cause reproductive toxicity. Avoid inhalation, ingestion, and prolonged contact.

⚠ Avoid direct contact of hot oil with your skin.

  1. Operate the engine until the water temperature is approximately 60 °C (140 °F).
  2. Shut down the engine.
  3. Drain the oil.
  4. Remove the oil filter and clean the filter mounting surface; remove the old gasket if it remains.
  5. Make sure the gasket is in place on the new filter, apply a thin film of clean oil to the gasket, install until the gasket just touches the block, then turn an additional 1/2 to 3/4 turn.
  6. Refill with oil until full.
  7. Start and run for 30 seconds.
  8. Shut the engine off and wait 5 minutes.
  9. Check the engine oil level.
  10. Dispose of the used oil and oil filter according to local environmental regulations.
Check the engine oil level maintenance

⚠ Crankcase pressure can blow out hot oil and cause severe burns. Do NOT check oil while the engine is operating.

  1. Pull out the dipstick and wipe it clean.
  2. Clean off the area surrounding the dipstick port to prevent entry of debris into the oil pan.
  3. Make sure that the engine has not been running for approximately five minutes.
  4. Reinsert and fully seat the dipstick.
  5. Remove the dipstick and check the oil level.
  6. Reinsert and fully seat the dipstick.
Draining oil maintenance

⚠ Ensure that the generator set engine has cooled down before adding or draining the oil.

  1. Detach the oil drain hose from the side of the engine.
  2. Place the end of the drain hose into an appropriate container.
  3. Open the oil drain valve to release oil from the engine into the container.
  4. Recheck the engine oil level. Based on results, add or drain oil.
  5. Close the oil drain valve, wipe it clean, and re-attach the drain hose.
  6. Dispose of the used oil in accordance with local/state regulations.
Exercise settings - update exercise frequency operation
  1. Press Exercise Schdr on the Daylight Saving Adjust End Menu.
  2. Press Adjust.
  3. Use + or - keys to edit Schdr Enable, Exercise Schedule, and Day/Hours/Minutes/AM-PM.
  4. Press Save to save any changes.
Screen brightness and contrast adjustment operation
  1. From any Information screen, hold down the up and down arrows simultaneously for two seconds to access the Service Menu screen.
  2. Select Screen Adjust.
  3. Select Adjust to access the screen variables.
  4. Press the right arrow to move between variables.
  5. Adjust settings, and press Save to save any changes.
Set up the clock (Time Setup) operation

⚠ When battery power is lost, these settings must be reset.

  1. Access the Time Setup Menu by selecting Clock Exerciser on the Genset Service Menu.
  2. Select Adjust.
  3. Use the right arrow to select blocks and + or - keys to adjust values.
  4. Press Save to save any changes.
Update exercise duration operation
  1. Press the down key on the Exercise Schdr Menu.
  2. Press Adjust.
  3. Use the horizontal right arrow key to select the duration block.
  4. Use the + or - keys to edit the exercise duration minutes.
  5. Press Save to save any changes.

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

VoltagePhaseConnectionLeadsNotes
120/208312-lead12
120/24014-lead4
120/240312-lead12

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 C22 N6?

The Cummins/Onan C22 N6 is rated 22 kW standby (22.0 kVA).

What engine does the Cummins/Onan C22 N6 use?

The Cummins/Onan C22 N6 is powered by the Cummins/Onan QSJ2.4 engine.

What fuel does the Cummins/Onan C22 N6 use?

The Cummins/Onan C22 N6 runs on natural gas or propane.

How much coolant does the Cummins/Onan C22 N6 hold?

The Cummins/Onan C22 N6 cooling system holds 12.8 liters (3.4 US gallons) for the engine, per the manufacturer specification sheet.

How much oil does the Cummins/Onan C22 N6 take?

The Cummins/Onan C22 N6 has an engine oil capacity of 4.3 liters (4.5 US quarts), per the manufacturer specification sheet.

How much does the Cummins/Onan C22 N6 weigh?

The Cummins/Onan C22 N6 has a dry weight of 1109 kg (2444 lb).

What voltages is the Cummins/Onan C22 N6 available in?

The Cummins/Onan C22 N6 is offered in 120/240 V, 120/208 V, 277/480 V, 1 or 3-phase.

What size battery does the Cummins/Onan C22 N6 need?

The Cummins/Onan C22 N6 uses 12 V each, [545, 850] CCA, group ['26 standard', '34 high capacity'], per the manufacturer specification sheet. The starting system is 12 V DC.

What alternator comes on the Cummins/Onan C22 N6?

The Cummins/Onan C22 N6 uses a Brushless, 2-pole rotating field, single bearing alternator. It has 2 poles.

What oil filter does the Cummins/Onan C22 N6 use?

The Cummins/Onan C22 N6 uses oil filter part number CA135-E12.

What air filter fits the Cummins/Onan C22 N6?

The Cummins/Onan C22 N6 uses air filter part number A046N985.

Troubleshooting

5

Fault codes

CodeMeaning
Code 143Engine Oil Pressure Low (Warning)
Code 146Engine Coolant Temperature Above Normal (Warning)
Code 151Engine Coolant Temperature High (Shutdown)

Symptoms & remedies

SymptomCauseRemedy
Any spillage that occurs during fueling or during oil top-off or oil change must be cleaned up before starting the generator set.Clean up any spillage before starting the generator set.
Fire HazardContaminated insulation is a fire hazard.Remove any contaminated insulation and dispose of it in accordance with local regulations.

Fault codes and symptom→remedy steps extracted from this model’s service/owner documentation; verify against the official manual before servicing.

Parts

13
Part #DescriptionQtySystem
A046N983Preventive Maintenance Kit –Heavy Duty2Air filter Amazon eBay
A046N985Preventive Maintenance Kit (Normal Duty Air Filter)2Air filter Amazon eBay
A046N987Preventive Maintenance Kit (Normal Duty Air Filter)2Air filter Amazon eBay
CA115-T12Large, Oil CoolerOil filter Amazon eBay
CA135-E12Large, Oil CoolerOil filter Amazon eBay
A046J612Base Barrier – Elevated Genset1Service part / kit Amazon eBay
A046L270Instruction Sheet1Service part / kit Amazon eBay
CA115-H14SmallService part / kit Amazon eBay
CA115-J12SmallService part / kit Amazon eBay
CA115-L14SmallService part / kit Amazon eBay
CA115-M12LargeService part / kit Amazon eBay
CA115-P12LargeService part / kit Amazon eBay
CA115-R12LargeService 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.

Available documents

Spec sheet (Cummins/Onan)Spec sheet — epa-1236Operator's manual — 2929 rx powerconnect operatormanual (Cummins/Onan)Reference — eds-1166Parts manual — 77789-1301Parts manual — NAACSB-6026-EN (Cummins/Onan)Service manual — 8023 rx powerconnect installmanual (Cummins/Onan)Service manual — C30N6 Service Manual (Cummins/Onan)Service manual — QSJ2.6 Generator Set Operator Manual (Cummins/Onan)Service manual — cummins-rs30-208-owners-manual (Cummins/Onan)

This page was generated from the 10 manufacturer documents above by automated extraction; every figure shown is copied from one of them. How the data is compiled.