Cummins/Onan DFAC — Specs, Engine, Parts & Maintenance

Specifications

Fuel	Diesel
Frequency	60.0 Hz
Standby power	250 kW
Standby kVA	313
Prime power	225 kW
Controller	Detector, PowerCommand, PowerCommand 2100, PowerCommand 3100
Oil capacity	36.0 L
Voltage options	110/190 V, 115/200 V, 120/208 V, 120/240 V, 127/220 V, 139/240 V, 220/380 V, 240/416 V, 254/440 V, 277/480 V, 347/600 V
Phase	three phase
Battery group	8D
Battery cranking	1400 CCA
Battery voltage	24 V
Battery quantity	2
Coolant capacity	49 L
Max ambient	50 °C
Dimensions (L×W×H)	3404×1270×1617 mm
Dry weight	2676 kg
Wet weight	2762 kg

Engine

Cummins/Onan LTA10

Oil capacity	36.0 L
Coolant capacity	49.0 L

Filters for the Cummins/Onan LTA10

Engine-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
Oil filter	P550777	Lube Filter, Spin-On Bypass	CUMMINS 3021658, CUMMINS 33004232, NAPA 1749, BALDWIN B7577	FridayParts $43.56
Oil filter	P551670	Lube Filter, Spin-On Full Flow	CUMMINS 298670, CUMMINS 299670, NAPA 1970, CARBOCOL 0026	FridayParts $26.68
Fuel filter	P550105	Fuel Filter, Spin-On Primary	CUMMINS 154700, CUMMINS 154710, NAPA 3109, NAPA 3405	buy
Fuel / water separator	P558000	Fuel Filter, Water Separator Spin-On Twist&Drain	CUMMINS 3308638, CUMMINS 3308683, NAPA 3405, NAPA 3693	KuduParts $24.00 FridayParts $25.66
Fuel / water separator	P550106	Fuel Filter, Water Separator Spin-On	CUMMINS 154789, CUMMINS 156164, NAPA 3405, BALDWIN BF957-D	FridayParts $285.60
Coolant filter	P554071	Coolant Filter, Spin-On	CUMMINS 209604, CUMMINS 209606, NAPA 4071, WALGAHN-MOTORENTECHN 00811412	FridayParts $397.60

Same engine, other brands

1 brand

The Cummins/Onan LTA10 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
AKSA	AC250, AC275

Maintenance & consumables

for the Cummins/Onan LTA10

Item	Spec	Capacity	Part #	Interval
Air filter			—
Fuel filter			—
Oil filter			—	268 hr
Battery			—
Belt			—
Coolant	-50	49.0	—
Oil	Cummins engine Operation and Maintenance Manual	36.0 L	—
Spark plug			—

Service intervals

Item	Action	Hours	Months	Notes
Rupture basin leak detect switch	Test		12 mo	Some areas may require weekly inspections by safety code.

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

Type	Item	Value	Unit	Condition
Clearance	Angular alignment T.I.R. limit	not more than .001	in per inch of radius	center of shaft to indicator axis
Clearance	Angular alignment maximum T.I.R.	0.001	inch per inch of radius (center of shaft to indicator axis)	measuring deflection to bolt heads
Clearance	Float switch assembly float lift clearance below C-clip stop	1/8	inch (3 mm)	use a feeler gauge
Clearance	Generator-to-engine angular alignment (T.I.R.)	.001 in. per inch of radius (center of shaft to indicator axis), maximum	in	750 kW gensets and larger
Clearance	MPU sensor to gear tooth adjustment	back out one quarter turn	turn	after contacting gear tooth
Clearance	Vibration isolator base elevation difference	0.25	inch (6 mm)	all isolator bases within this elevation of each other
Clearance	Vibration isolator clearance between top plate and base	0.25	inch (6 mm)	nominal or greater
Clearance	Vibration isolator top plate to base clearance	0.25	inch (6 mm)	nominal, or greater
Gap	Angular alignment total indicator reading (T.I.R.)	0.001	inch per inch of radius	maximum
Gap	Float switch lift to test open	1/8	inch	below C-clip stop
Gap	MPU sensor to flywheel ring gear tooth	back it out one quarter turn	turn	sensor threaded in until it just touches gear tooth
Other	AVR Droop setting	5	% at full load, 0 PF
Other	AVR voltage regulation (load regulation)	approximately ±0.5	% RMS
Other	Angular alignment maximum T.I.R.	.001	inch per inch of radius	center of shaft to indicator axis
Other	Angular alignment maximum T.I.R.	.001 inches per inch of radius	in/in	center of shaft to indicator axis
Other	Battery specific gravity (high ambient, above 95F/35C)	1.225		recommended to reduce electrolyte loss
Other	Battery specific gravity (recharge threshold)	below 1.260
Other	Battery specific gravity, fully charged	approximately 1.260	specific gravity	at 80 F (27 C)
Other	Fuel lift height limit	6	feet	(1.8 meters) between fuel lift pump and bottom of dip tube
Other	GOV GAIN default value for paralleling applications	70	%
Other	Maximum cranking voltage drop	2	volts	difference between battery and starter terminals while cranking
Other	Over/Under Frequency Sensor Module - Over Hz Set, 50 Hz nominal	55	Hz	reset 53 Hz
Other	Over/Under Frequency Sensor Module - Over Hz Set, 60 Hz nominal	65	Hz	reset 63 Hz
Other	Over/Under Frequency Sensor Module - Under Hz Set, 50 Hz nominal	45	Hz	reset 47 Hz
Other	Over/Under Frequency Sensor Module - Under Hz Set, 60 Hz nominal	55	Hz	reset 57 Hz
Other	Over/Under Voltage Sensor Module time delay	typically 25 percent, approximately 2.5	seconds
Other	Overcrank cranking limit	75	seconds	three 15-second cranking cycles with two 15-second rest periods
Other	Overcurrent shutdown threshold	110% of rated	% of rated	PCC time/current calculation
Other	Overcurrent warning threshold	110% of rated for 60 seconds	% of rated	generator output current
Other	Overload warning threshold	105% of standby or 115% of prime	% of rating	three-phase power output; load dump after five seconds, warning after 60 seconds
Other	REG VHZ (underfrequency roll-off) adjustable range	1 through 50; normal range 7 through 21
Other	Short circuit shutdown threshold	175% of rated	% of rated	generator output current
Other	Start delay adjustment range	0 to 300	seconds
Other	Stop delay adjustment range	0 to 600	seconds
Other	Under Frequency Roll Off (UFRO) knee point, 50 Hz units	48 to 49	Hz
Other	Under Frequency Roll Off (UFRO) knee point, 60 Hz units	58 to 59	Hz
Other	Under-frequency roll-off threshold (UFRO)	typically 59 Hz for 60 Hz applications and 49 Hz for 50 Hz applications	Hz	AVR UFRO pot preset
Other	Weak battery warning threshold	below 60% of nominal for two seconds	% of nominal	during starting
Pressure	Engine oil pressure - K19 normal	50-70	psi (345-482 kPa)	run mode
Pressure	Engine oil pressure - K38 normal	45-65	psi (310-448 kPa)	run mode
Pressure	Engine oil pressure - K50 normal	50-70	psi (345-482 kPa)	run mode
Pressure	Engine oil pressure - L10/M11 normal	30-50	psi (207-345 kPa)	run mode
Pressure	Engine oil pressure - NTA 855 normal	35-50	psi (241-345 kPa)	run mode
Pressure	Engine oil pressure - V28 normal	50-90	psi (345-620 kPa)	run mode
Pressure	Engine oil pressure shutdown limit - L10/M11	20	psi (138 kPa)	run mode value
Pressure	Engine oil pressure shutdown limit - L10/M11	8	psi (55 kPa)	idle mode value
Pressure	Engine oil pressure warning limit - L10/M11	12	psi (83 kPa)	idle mode value
Pressure	Engine oil pressure warning limit - L10/M11	25	psi (172 kPa)	run mode value
Pressure	K19 engine idle oil pressure	20	psi (138 kPa)	idle
Pressure	K19 engine normal oil pressure	50-70	psi (345-482 kPa)	normal run
Pressure	K19 normal oil pressure (run/idle)	50-70 / 20	psi (345-482 / 138 kPa)	NORM run / IDLE
Pressure	K19 oil pressure shutdown limit	10	psi (69 kPa)	idle mode
Pressure	K19 oil pressure shutdown limit	35	psi (241 kPa)	run mode
Pressure	K19 oil pressure shutdown/warning limits	shutdown 35 psi (241 kPa) run; warning 40 psi (276 kPa) run; shutdown 10 psi (69 kPa) idle; warning 15 psi (103 kPa) idle	psi (kPa)
Pressure	K19 oil pressure warning limit	15	psi (103 kPa)	idle mode
Pressure	K19 oil pressure warning limit	40	psi (276 kPa)	run mode
Pressure	K38 engine idle oil pressure	20	psi (138 kPa)	idle
Pressure	K38 engine normal oil pressure	45-65	psi (310-448 kPa)	normal run
Pressure	K38 normal oil pressure (run/idle)	45-65 / 20	psi (310-448 / 138 kPa)	NORM run / IDLE
Pressure	K38 oil pressure shutdown limit	10	psi (69 kPa)	idle mode

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
Coolant	soft water / E.G. / DCA mixture				Cooling system to be filled with soft water/E.G./DCA mixture (on-site review checklist).
Coolant		NFPA 110	above 4°C		NFPA 110 recommends engine jacket water coolant heaters where minimum ambient is above 40°F (4°C); coolant maintained at minimum 90°F (32°C). Cooling system capacity with standard radiator: DFAB/DFAC 13 Gal (49 L); DFBF 13.5 Gal (51 L); DFCC 13.5 Gal (51 L); DFCE 15 Gal (57 L).
Fuel	ASTM No. 2 diesel	Cummins engine Operation and Maintenance Manual alternate diesel fuels			Cummins engines normally use ASTM No. 2 diesel fuel. Never use galvanized or copper fuel lines, fittings or fuel tanks.
Fuel	ASTM No. 2 diesel fuel	ASTM No. 2			Cummins engines normally use ASTM No. 2 diesel fuel; they will operate on alternate diesel fuels within the specifications shown in the Cummins engine Operation and Maintenance Manual. Never use galvanized or copper fuel lines, fittings or fuel tanks.
Fuel	Diesel				Day tank fuel transfer pump maintains reservoir of diesel fuel in the day tank.
Fuel	number 2 diesel fuel				Direct injection fuel system
Grease	Lithium based grease	Mobilux No. 2 or Shell Alvania R3		2.74 oz (81 ml)	Generator end bearing. Temperature range -22F to +248F (-30C to +120C). Grease should be equally divided between the bearing, bearing cap cavity, and bearing cartridge cavity.
Grease	Lithium based		-30°C to 120°C	81.0 ml	Mobilux No. 2 or Shell Alvania R3; generator end bearing; temperature range -22 F to +248 F (-30 C to +120 C); grease divided between bearing, bearing cap cavity and cartridge cavity.
Grease	Lithium based grease, Mobilux No. 2 or Shell Alvania R3		-30°C to 120°C	2.74 oz (81 ml)	End bearing lubricant; grease equally divided between bearing, bearing cap cavity and bearing cartridge cavity.

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

Code	Name	Meaning	Severity	Action
101	IDLE MODE	Indicates that the engine is operating in idle mode (governed at 800 RPM, generator build-up inhibited).	Warning	Remove ground from engine idle input to return to normal speed and voltage.
102	EMERGENCY STOP	Indicates local or remote Emergency Stop.	Shutdown	Turn the switch clockwise and allow it to pop out (local only). Move the Run/Off/Auto switch to Off. Press the Reset switch. Select Run or Auto, as required.
121	SPEED SIGNAL LOST	Mag pickup speed indication is not being sensed.	Shutdown	Restart and check RPM on the digital display.
135	OIL PRESSURE SENSOR H	Engine oil pressure sender signal is shorted high.	Warning	Check sender/connectors/wires.
141	OIL PRESSURE SENSOR L	Engine oil pressure sender signal is shorted low.	Warning	Check sender/connectors/wires.
143	PRE-LOW OIL PRES	Engine oil pressure has dropped to an unacceptable level.	Warning	If critical loads, wait until next shutdown period and follow code 415.
144	COOL SENSOR HIGH	Engine coolant temperature signal is shorted high.	Warning	Check sender/connectors/wires.
145	COOL SENSOR LOW	Engine coolant temperature signal is shorted low.	Warning	Check sender/connectors/wires.
146	PRE-HIGH COOL TMP	Engine has begun to overheat.	Warning	Reduce load; check air inlets/outlets; follow code 151 if engine can be stopped.
151	HIGH COOLANT TEMP	Engine has overheated above the shutdown trip point.	Shutdown	Allow cool down; check coolant level, cooling airflow, fan belt, blower fan and circulation pumps.
197	LOW COOLANT LEVEL	Engine coolant level has fallen below the warning trip point.	Warning	Check coolant level and replenish if low; reset control.
200	LOW OIL PRESSURE	Indicates engine oil pressure has dropped to an unacceptable level.	Warning	If generator is powering critical loads and cannot be shut down, wait until next shutdown period and then follow 201-SHUTDOWN procedure. Access the Oil Pressure menu prior to clearing the fault.
201	LOW OIL PRESSURE	Indicates engine oil pressure has dropped below the shutdown trip point.	Shutdown	Check oil level, lines and filters. If oil system is OK but oil level is low, replenish. Reset control and restart. Oil pressure limits are listed in Table 4-3.
204	OIL PRES SENDER	Indicates that the control has sensed that the engine oil pressure sender is out of its working range.	Warning	Check that the engine oil pressure sender is properly connected.
210	LOW COOLANT TEMP	Set is not operating. Warning occurs when engine coolant temperature is 70° F (21° C) or lower.	Warning	Indicates engine coolant heater is not operating or is not circulating coolant. Check coolant heater power supply, low coolant level, and heater element current draw.
211	HIGH COOLANT TEMP	Indicates the engine coolant temperature is getting close to the recommended maximum temperature limit: 215° F (102° C) − standby or 207° F (97° C) − primary.	Warning	Reduce load if possible by turning off non-critical loads. Check air inlets and outlets and remove any obstructions to airflow. If engine can be stopped, follow 212-SHUTDOWN procedure.
212	HIGH COOLANT TEMP	Indicates engine has overheated (coolant temperature above 215° F (102° C) − standby or 207° F (97° C) − primary).	Shutdown	Allow engine to cool down completely. Check for obstructions to cooling airflow; check fan belt; check coolant mixture; check blower fan and circulation pumps on remote radiator installations. Reset control and restart.
213	COOLANT SENDER	Indicates that the resistance of the coolant temperature sender is out of range.	Warning	Check the resistance of the sender. Resistance should be 500 to 2k ohms.
214	LOW COOLANT LVL	Indicates engine coolant level has fallen below the trip point.	Warning	Allow engine to cool down completely. Check coolant level in both radiator and coolant recovery bottle and replenish if low. Look for coolant leakage points and repair if necessary.
215	LOW COOLANT LVL	Indicates engine coolant level has fallen below the trip point.	Shutdown	Allow engine to cool down completely. Check coolant level in both radiator and coolant recovery bottle and replenish if low. Reset control and restart after correcting problem. Shutdown will not occur if genset is in Idle mode (low coolant warning only).
220	MAG PICKUP	Indicates mag pickup speed indication is not being sensed or does not match generator set output frequency.	Shutdown	Restart and check RPM on the digital display.
221	FAIL TO CRANK	Indicates possible fault with control or starting system.	Shutdown	Check fuse F3 on the Engine Interface board. Check for poor battery cable connections; clean battery cable terminals and tighten. Recharge or replace a discharged or defective battery.
222	OVERCRANK	Indicates possible fuel system problem.	Shutdown	Check for empty fuel tank, fuel leaks, or plugged fuel lines. Check for dirty fuel filter and replace if necessary. Check for dirty or plugged air filter and replace if necessary. Reset the control and restart after correcting the problem.
223	OVERSPEED	Engine has exceeded normal operating speed (115% ±1% of nominal).	Shutdown	Check mechanical fuel linkage and actuator; check governor output module (A38) and digital board (A32).
224	FAIL TO SYNCHRONIZE	Generator set has not synchronized to the system bus within the allowable time frame.	Warning	Check governor system stability; adjust governing and synchronizer parameters; check fuel system.
226	FAIL TO CLOSE	Paralleling breaker has been given a signal to close, but has not closed properly.	Shutdown	Verify breaker charging mechanism; check close signal; verify auxiliary contact signals.
230	LOW DC VOLTAGE	Indicates battery voltage is below 10 VDC.	Warning	Recharge or replace the battery; check the battery charger fuse. Clean and tighten battery cable connections. Check engine DC alternator; replace if normal charging voltage is not obtained. Check float level if applicable.
231	HIGH DC VOLTAGE	Indicates battery voltage exceeds 32 VDC.	Warning	Check float level on battery charger if applicable (lower float level). Check engine DC alternator; replace if normal battery charging voltage is not obtained.
232	WEAK BATTERY	Indicates battery voltage drops below 60% of nominal for two seconds, during starting.	Warning	Discharged or defective battery. See Warning message 230, LOW DC VOLTAGE.
234	OVERSPEED	Engine has exceeded normal operating speed.	Shutdown	Check for large block load removal, flammable vapors or leaking turbocharger seals.
235	LOW COOLANT LEVEL	Engine coolant level has fallen below the shutdown trip point.	Shutdown	Check coolant level and replenish if low; reset control.
240	LOW FUEL−DAY	Indicates day tank fuel supply is running low.	Warning	Check fuel supply and replenish as required.
241	LOW FUEL	Indicates day tank fuel supply is running low.	Warning	Check fuel supply and replenish as required.
250	EEPROM ERROR	PCC memory error; data corruption of critical operating parameters.	Shutdown	Perform initial start setup procedure; replace digital board (A32) if fault repeats.
251	EEPROM ERROR	PCC memory error; data corruption of noncritical operating parameters.	Warning	Perform adjustment and calibration procedures; replace digital board (A32) if fault repeats.
252	EEPROM ERROR	PCC memory error; data corruption of noncritical operating parameters.	Warning	Verify selected values; repeat save operation; replace digital board (A32) if fault repeats.
260	CUSTOMER FAULT 1	When a customer defined input is closed to ground, the corresponding fault message is displayed. Default message; editable for customer site requirements.	Warning	Fault functions can be programmed to initiate a shutdown or a warning.
261	GROUND FAULT	When a customer defined input is closed to ground, the corresponding fault message is displayed. Default message; editable for customer site requirements.	Warning	Fault functions can be programmed to initiate a shutdown or a warning.
262	RUPTURE BASIN	When a customer defined input is closed to ground, the corresponding fault message is displayed. Default message; editable for customer site requirements.	Warning	Fault functions can be programmed to initiate a shutdown or a warning.
263	HIGH GEN TEMP	When a customer defined input is closed to ground, the corresponding fault message is displayed. Default message; editable for customer site requirements.	Warning	Fault functions can be programmed to initiate a shutdown or a warning.
270	PHASE ROTATION	The phase relationship between the generator set and the system bus is not matched.	Shutdown	Verify genset phase rotation matches bus; verify control wiring to bus PT module.
272	FIRST START	PowerCommand control is not receiving a proper signal from the system master first start sensor.	Warning	Verify Master First Start Sensor and interconnection wiring.
301	HIGH AC VOLTAGE	One or more phase voltages exceeded 130% of nominal, or exceeded 110% of nominal for 10 seconds.	Shutdown	Check PCC, alternator, excitation circuit, and PT/CT module wiring.
303	LOW AC VOLTAGE	One or more phase voltages dropped below 85% of nominal for 10 seconds.	Shutdown	Check PMG/field wiring, rotating rectifier, load and connectors.
313	UNDER FREQUENCY	Indicates that engine speed has dropped below 90% of nominal for 10 seconds. Five seconds before shutdown, a Load Dump signal is initiated.	Shutdown	Check fuel supply, intake air supply and load.
320	OVERCURRENT	Indicates that generator output current has exceeded 110% of rated for 60 seconds.	Warning	Check load and load lead connections.
321	OVERCURRENT	Indicates that generator output current has exceeded 110% of rated, and that a PCC time/current calculation has initiated an overcurrent shutdown.	Shutdown	Check load and load lead connections.
322	SHORT CIRCUIT	Indicates that generator output current has exceeded 175% of rated.	Shutdown	Check load and load lead connections.
330	OVERLOAD	Indicates that three-phase power output exceeds 105% of standby (or 115% of prime) rating. After five seconds, the Load Dump output is activated. After 60 seconds, the OVERLOAD warning is activated.	Warning	Check load and load lead connections.
335	REVERSE POWER	Indicates improper CT or PT phasing. (Non-parallel units only.)	Shutdown	Check CT / PT wiring. Refer to CT Installation in Section 5.
337	LOSS OF EXCITATION	Alternator excitation system is improperly adjusted or has failed.	Shutdown	Check output voltage calibration, load sharing lines, and leading power factor loads.
359	FAIL TO START	Engine cranks but fails to start after last crank time.	Shutdown	Check fuel tank, leaks, fuel lines, fuel filter, air filter; check fuel solenoid and actuator.
415	LOW OIL PRESSURE	Engine oil pressure has dropped below the shutdown trip point.	Shutdown	Check oil level, lines and filters; replenish if low; reset control.
421	OIL TEMP	Engine oil temperature has exceeded the warning threshold.	Warning	Reduce load; check air inlets/outlets; check engine oil level.
441	LOW BAT VOLTAGE	Battery voltage supply to the control is approaching a low level.	Warning	Recharge or replace battery; check charger fuse, connections and DC alternator.
442	HIGH BAT VOLTAGE	Battery voltage supply is approaching a high level.	Warning	Check battery charger float level; check battery wiring/calibration.
1123	SHUTDOWN AFTER BS	Shutdown fault occurred while Battle Short was enabled and then disabled.	Shutdown	Review Fault History and perform corrective action.
1124	DELAYED SHUTDOWN	Shutdown fault became active while Delayed Shutdown feature was enabled.	Warning	Review Fault History and perform corrective action.
1131	BATTLE SHORT ACTIVE	Control is in Battle Short mode.	Warning	Bypasses several critical fault shutdowns for emergency operation.
1311, 1312, 1317, 1318	CUSTOMER INPUT #1 - #4	Optional customer-selected fault input is active.	Warning	Check external wiring and active input (closed/open) selection.
1334	CRIT SCALER OR	Incorrect feature or calibration entered into control.	Shutdown	Reload correct calibration.
1335	NONCRIT SCALER OR	Incorrect feature or calibration entered into control.	Warning	Reload correct calibration.
1416	FAIL TO SHUTDOWN	Genset continues to run after shutdown command.	Warning	Check Battle Short feature enabled condition.
1417	POWER DOWN ERROR	Controller cannot power down.	Warning	Check for possible battery drain.
1433	EMERGENCY STOP	Local Emergency Stop.	Shutdown	Pull button out; move switch to O; press Fault Acknowledge/Reset; select Manual or Auto.
1434	REMOTE E-STOP	Remote Emergency Stop.	Shutdown	See code 1433 to reset.
1435	Engine Cold	Engine jacket water coolant temperature falls below 70°F (21°C); Warning LED illuminated (provided to meet NFPA 110 requirements)	Warning	Check the coolant heaters for proper operation
1438	FAIL TO CRANK	Engine failed to crank after PCC received a start signal.	Shutdown	Check starter, fuse F3, K4 relay, E-Stop switch and MPU circuit.
1442	WEAK BATTERY	Battery voltage at or below weak battery warning trip point during cranking.	Warning	See code 441 for corrective action.
1443	BATTERY FAILED	Dead battery - engine will not start.	Shutdown	See code 441 for corrective action.
1444	KW OVERLOAD	Generator output power exceeded 105% of genset rating.	Warning	Check load and load lead connections; check CTs.
1445	SHORT CIRCUIT	Generator output current has exceeded 175% of rated.	Shutdown	Check load and load lead connections.
1446	HIGH AC VOLTAGE	One or more phase voltages exceeded 130% of nominal.	Shutdown	Check fault simulation, load removal, threshold settings, Base board/generator.
1447	LOW AC VOLTAGE	Phase voltages dropped below 85% of nominal for 10 seconds.	Shutdown	Check overload, output terminal connections, PMG/field wiring, rectifier diodes.
1448	UNDER FREQUENCY	Engine speed dropped below 90% of nominal for 10 seconds.	Shutdown	Check fuel supply, intake air supply and load.
1449	OVER FREQUENCY	Frequency is 10% above base frequency for 20 seconds.	Warning	Check fuel or air delivery; check connections.
1452	GEN CB NOT CLOSE	Genset circuit breaker (S2) failed to close when PTC is enabled.	Warning	Refer to Section 5 troubleshooting charts.
1453	GEN CB NOT OPEN	Genset circuit breaker (S2) failed to open when PTC is enabled.	Warning	Refer to Section 5 troubleshooting charts.
1459	REVERSE POWER	Improper CT phasing.	Shutdown	Check wiring to voltage sense circuit; refer to CT Installation in Section 6.
1461	LOSS OF FIELD	Loss of field (electric) due to reverse kVAR.	Shutdown	Check excitation circuit.

Showing the first 80 of 125 codes.

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

Procedures

Adjust Start/Stop Delays (PCC Adjust Menu) adjustment

⚠ Electrostatic discharge will damage circuit boards. Always wear a grounding wrist strap when working inside control box.

Press the button next to ADJUST in the Main Menu; the VOLTAGE submenu appears.
Press the button next to >> to move through VOLTAGE and FREQUENCY to the START DELAY submenu.
Use the buttons next to the up and down symbols to set the start delay.
Press >> to move to the STOP DELAY submenu and set the stop delay.
Press >> to move to the IDLE SPEED submenu and set idle speed (only in idle mode).
Press >> to move to SAVE/EXIT; select SAVE then EXIT to return to Main menu.

Adjusting Values/Parameters (PCC Adjust Menu) adjustment

Press the button next to the arrow symbol in the display until the + and - symbols are displayed.
If necessary, press the button next to the arrows to move to the numeric character to change.
Press + to increase the value or select the parameter; press - to decrease the value or select the parameter.
Press the save symbol to save changes; changes are not saved if Home or Previous Main Menu is pressed first.

Aligning Generator with Engine (Angular Alignment) adjustment

⚠ Accidental starting of the generator set during this procedure presents the hazard of severe personal injury or death.

Tools: Dial indicator, Shims

Disconnect the negative (-) battery cable(s) before beginning.
Fasten a dial indicator to the generator shaft or cooling fan with the sensing point on the capscrew head or flat surface of the drive disc at the bolt circle diameter.
Bar the engine over in a clockwise rotation as viewed from engine flywheel; do not allow it to roll back on compression.
Determine the total indicator reading (T.I.R.) as the sum of the maximum positive and negative dial indicator readings over one revolution.
Measure the distance from the center of the generator shaft to the indicator measuring point.
Measure the distance from the generator side of the flex discs to the center of the generator mounting bolt.
Compare the distances; multiply this ratio times one half the T.I.R. to approximate the amount of shims to remove or add.

Angular Alignment Procedure adjustment

⚠ Accidental starting of the generator set during this procedure presents the hazard of severe personal injury or death. Make sure to disconnect the negative (-) battery cable(s) before beginning.

Tools: Dial indicator, Wooden shims

Disconnect the negative (-) battery cable(s) before beginning.
Fasten a dial indicator to the generator shaft or cooling fan with sensing point on capscrew head or flat surface of drive disc at bolt circle diameter.
Bar the engine over in a clockwise rotation as viewed from engine flywheel; do not allow it to roll back on compression.
Record maximum positive and negative dial indicator readings as the engine completes one revolution.
T.I.R. equals the sum of the maximum positive and negative readings.
Maximum T.I.R. should not be more than .001 inch for each inch of radius.
Remove equal shims from under both generator mounting feet to lower the generator.

Angular Alignment Procedure (750 kW Gensets and Larger) adjustment

⚠ Accidental starting of the generator set during this procedure presents the hazard of severe personal injury or death. Make sure to disconnect the negative (-) battery cable(s) before beginning.

⚠ Do not bar engine over by prying on fan blade.

Tools: Dial indicator, Shims

Disconnect the negative (-) battery cable(s) before beginning.
Fasten a dial indicator to the generator shaft or cooling fan, with the sensing point on the capscrew head or drive disc flat surface at bolt circle diameter.
Bar the engine over clockwise as viewed from the engine flywheel; do not allow it to roll back on compression.
Total indicator reading (T.I.R.) is the sum of the maximum positive and negative readings as the engine completes one revolution.
To lower the generator, remove equal shims from under both generator mounting feet; approximate shim amount from the distance ratio.

Angular Alignment Procedure (Generator to Engine) adjustment

⚠ Accidental starting during this procedure presents the hazard of severe personal injury or death.

⚠ Do not bar engine over by prying on fan blade.

Tools: dial indicator

Disconnect the negative (-) battery cable(s) before beginning.
Fasten a dial indicator to the generator shaft or cooling fan with sensing point resting on the drive disc capscrew head/flat surface at the bolt circle diameter.
Bar the engine over in a clockwise rotation as viewed from the engine flywheel; do not allow it to roll back on compression at the end of travel of each reading.
Record the total indicator reading (T.I.R.) as the sum of the maximum positive and negative dial indicator readings over one engine revolution.
Compare the measured T.I.R. to the maximum allowed (.001 in. per inch of radius from center of shaft to indicator axis); add or remove shims under the generator mounting feet to correct.

Axial Alignment Procedure adjustment

Tools: Dial indicator, Magnetic base or clamp

Check axial alignment only when an objectionable vibration is present after angular alignment.
Fasten dial indicator holding device to skid base, engine block, or generator shell with a magnetic base or clamp; rest sensor on generator shaft hub.
Bar the engine over clockwise through a couple of rotations; record indicator readings at eight equally spaced points around the shaft diameter.
To correct out-of-tolerance T.I.R., remove the drive disc capscrews, mark discs and flywheel, rotate 180 degrees from original location, retorque, and recheck.
If unchanged, rotate the discs to 30, 60 or 90 degrees from their original location.

Axial Alignment Procedure (Generator to Engine) adjustment

Tools: dial indicator

Fasten a dial indicator holding device to the skid base, engine block, or generator shell with the sensor point resting on the generator shaft hub.
Bar the engine over in a clockwise rotation through a couple of rotations, recording indicator readings at eight equally spaced points around the shaft diameter to obtain axial T.I.R.
Reduce the measured T.I.R. runout by one half if excessive vibration remains after angular alignment.

Governor Calibration Checks adjustment

Tools: Frequency meter or tachometer, Jumper wire

Start the generator set.
Adjust engine no-load speed to the desired allowable speed droop using the Run Speed potentiometer.
With no load, turn GAIN clockwise slowly until engine speed oscillates.
Reduce GAIN slowly counterclockwise until engine speed is stable.
Upset the governor by momentarily shorting terminals 7 and 10 on the governor control.
Apply and remove loads to check generator set response.

HC4-7 Axial Alignment Procedure adjustment

Tools: Dial indicator with magnetic base or clamp

Check only when an objectionable vibration is present.
Fasten dial indicator holding device to skid base, engine block, or generator shell with magnetic base or clamp.
Position sensor point on the generator shaft hub.
Bar the engine over in a clockwise rotation as viewed from engine flywheel through a couple of rotations.
Record indicator readings in eight equally spaced points around the shaft diameter.
Remove the capscrews connecting drive discs and flywheel and mark discs and flywheel.
Rotate engine or generator so drive disc holes are repositioned 180 degrees from original location.
Put capscrews back in and retorque. Recheck shaft alignment.
If runout unchanged, rotate discs to 30, 60 or 90 degrees from original location.
If T.I.R. does not improve, inspect flywheel pilot and drive disc runouts.

P7 Axial Alignment Procedure adjustment

Check only when an objectionable vibration is present.
Remove the capscrews connecting drive discs and flywheel.
Mark the drive discs and flywheel with respect to each other.
Rotate engine or generator so drive discs holes are repositioned two bolt holes from original location.
Put capscrews back in and retorque. Recheck/record vibration levels.
Repeat this test until drive disc holes are repositioned 180 degrees from original location.
Review vibration data and position drive disc in lowest recorded level location.

UFRO Adjustments adjustment

⚠ Use an insulated handle screw driver to prevent electrical shock.

Tools: Insulated handle screwdriver, Frequency meter or tachometer

Make a note of the no-load frequency.
Determine roll-off frequency by turning the governor speed pot until the LED lights; if okay go to step 5.
Adjust the governor speed pot to the proper roll-off frequency.
Turn the UFRO pot until LED goes off, then slowly turn it back until the LED just goes on.
Adjust the governor speed pot back to the initial frequency setting.

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
		12 lead generator sets	Load wires are routed through the CTs	Reconnectable gensets (12 leads) have dual secondary CTs (3 pins); CT wire 2/3 to pin 2 (high voltage) or pin 3 (low voltage).
		6 lead generator sets	Generator output leads are routed through the CTs	Non-reconnectable gensets (6 leads) have single secondary CTs (2 pins).
		Cummins PowerCommand generic AC Reconnect Wiring Diagram 625-2755 (Rev. D) and 625-3100 (Rev. F)		Applies to models DFAA, DFAB, DFAC, DFBF, DFCB, DFCC, DFEB, DFEC, DFFB, DFGA, DFGB, DFJA, DFJB, DFJC, DFJD, DFLB, DFLC, DFLD, DFMB (625-2755) and models DFAA-DFMB plus DFCE, DFED, DQAA, DQAB, DQBA, DQBB (625-3100).
		Current transformers CT21-U load leads (A phase), CT22-V load leads (B phase), CT23-W load leads (C phase)	CT secondary wire marked 1 to pin 1; wire marked 2/3 to pin 2 for high voltage gensets or pin 3 for low voltage gensets	CT dot must face toward the generator; CTs have dual secondaries (3 pins).
		Generator load terminals stamped U, V, W and N (U=L1, V=L2, W=L3, N=L0)	Stranded load wires bolted to generator reconnection terminal block or circuit breaker lugs	Available generator output voltages and maximum current ratings are specified on the generator set nameplate; line-to-neutral is the lower voltage, line-to-line the higher. Reconnection diagram is located on the upper side cover of the control housing.
	A	CT21 – U load leads	A phase	CT dot must face the generator; CT terminal 1 connects to metering circuit; terminal 2/3 connects to ground.
	A (U)	Bus PT module TB1 A	bus A phase	Bus PT module A39.
	A (U)	CT21	U load leads (A phase)	CT dot must face the generator; CT terminal 1 connects to metering circuit, terminal 2/3 to ground.
	B	CT22 – V load leads	B phase	CT dot must face the generator; CT terminal 1 connects to metering circuit; terminal 2/3 connects to ground.
	B (V)	Bus PT module TB1 B	bus B phase	Bus PT module A39.
	B (V)	CT22	V load leads (B phase)	CT dot must face the generator; terminal 1 to metering circuit, terminal 2/3 to ground.
	C	CT23 – W load leads	C phase	CT dot must face the generator; CT terminal 1 connects to metering circuit; terminal 2/3 connects to ground.
	C (W)	Bus PT module TB1 C	bus C phase	Bus PT module A39.
	C (W)	CT23	W load leads (C phase)	CT dot must face the generator; terminal 1 to metering circuit, terminal 2/3 to ground.
	N	Bus PT module TB1 N	bus neutral	Bus PT module A39.
110 V - 120 V L-N	1	Single phase, 2-wire		PTC module jumper locations
190 V - 240 V L-L	3	Three phase		Use PTC module 0300-5382-01; 50/60 Hz
200 V - 240 V L-L	1	Single phase, 3-wire		PTC module jumper locations
380 V - 600 V L-L	3	Three phase		Use PTC module 0300-5382-02; 50/60 Hz
high voltage genset		12-lead CT secondary wire marked 2/3 to pin 2	2/3	For high voltage gensets.
low voltage genset		12-lead CT secondary wire marked 2/3 to pin 3	2/3	For low voltage gensets.

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

How many kW is the Cummins/Onan DFAC?

The Cummins/Onan DFAC is rated 250 kW standby (313.0 kVA).

What engine is in the Cummins/Onan DFAC?

The Cummins/Onan DFAC is powered by the Cummins/Onan LTA10 engine.

Is the Cummins/Onan DFAC diesel or gas?

The Cummins/Onan DFAC runs on Diesel.

What's the oil capacity on a Cummins/Onan DFAC?

The Cummins/Onan LTA10 engine in the Cummins/Onan DFAC has an oil capacity of 36.0 liters.

How much coolant does the Cummins/Onan DFAC hold?

The Cummins/Onan DFAC cooling system holds 49 liters (12.9 US gallons) for the radiator system including the engine, per the manufacturer specification sheet.

What is the prime power rating of the Cummins/Onan DFAC?

The Cummins/Onan DFAC is rated 225 kW prime (281 kVA), against 250 kW standby.

What is the dry weight of the Cummins/Onan DFAC?

The Cummins/Onan DFAC has a dry weight of 2676 kg (5899 lb).

What voltages is the Cummins/Onan DFAC available in?

The Cummins/Onan DFAC is offered in 110/190 V, 115/200 V, 120/208 V, 120/240 V, 127/220 V, 139/240 V, three phase-phase.

What battery does the Cummins/Onan DFAC use?

The Cummins/Onan DFAC uses 2 batteryies, 24 V each, 1400 CCA, group 8D, per the manufacturer specification sheet.

Troubleshooting

Fault codes

Code	Meaning	Cause	Remedy
101	IDLE MODE — WARNING; Engine continues to operate at reduced RPM.	Indicates that the engine is operating in idle mode. When the set is operating in the RUN mode, grounding the engine idle input causes generator build-up to be inhibited and the engine to be governed at 800 RPM.	When ground is removed from this input, the set returns to normal speed and voltage. When the engine idle function is enabled, the control automatically sets lower oil pressure warning and shutdown trip points to reflect the lower operating speed. When the engine idle function is removed and the set reverts to normal operating speed, the control automatically resets oil pressure warning and shutdown trip points to the normal settings.
102	EMERGENCY STOP — SHUTDOWN; Engine shuts down and will not crank.	Indicates local or remote Emergency Stop.	To reset the local Emergency Stop button: Pull the button out or turn the switch clockwise (button with arrow) and allow it to pop out; Move the Run/Off/Auto switch to Off; Press the Reset switch; Select Run or Auto, as required.
200	LOW OIL PRESSURE — WARNING	Indicates engine oil pressure has dropped to an unacceptable level.	If generator is powering critical loads and cannot be shut down, wait until next shutdown period then follow 201 Low Oil Pressure procedure. If engine can be stopped, follow 201 procedure. To check oil pressure, access Oil Pressure menu prior to clearing the fault.

Symptoms & remedies

Symptom	Cause	Remedy
Control does not power up when the Run/Off/Auto switch is set to Run or the Self Test switch is pressed.	There is no DC power to the control.	Check for battery disconnected, discharged, or improperly connected; Fuse F1 (20A/32V, Type 3AG) may be open. Replace with the same type. (Fuse is mounted near engine starter/solenoid, see Figure 4-2); Contact an authorized service center.
Warning, Shutdown, and Non-Automatic lamps are not lit. Digital display shows main menu or selected menu.	Indicates all engine systems are normal.	No corrective action required.
Non-Automatic lamp flashes.	Indicates Run/Off/Auto switch is not in the Auto position. This will prevent automatic starting if an automatic transfer switch is used.	Move the Run/Off/Auto switch to the Auto position for automatic operation.

Fault codes and symptom→remedy steps extracted from this model’s service/owner documentation; verify against the official manual before servicing. Full Cummins/Onan DFAC troubleshooting guide (115 entries) →

Repair guides

Step-by-step procedures compiled from the Cummins/Onan service manual for this model.

Parts

Part #	Description	Qty	System
0300-4623-05	DFAA (600V)	1	Current transformer	Amazon eBay
0300-4623-06	DFAB (600V)	1	Current transformer	Amazon eBay $153.95
0300-4623-07	DFAC (600V)	1	Current transformer	Amazon eBay
0300-4623-17	DFAA BR (0-480V)	1	Current transformer	Amazon eBay $165.95
0300-4623-19	DFAB BR (0-480V)	1	Current transformer	Amazon eBay
0300-4623-21	DFAC BR (0-480V)	1	Current transformer	Amazon eBay
960-0167	Battery, Group Number: 8D, CCA (minimum): 1400, Cold Soak® -40°F (-40°C)	2	Battery	Amazon eBay
A40-TB1-2	SWITCHED B+		Belt	Amazon eBay
A40-TB1-4	GROUND		Belt	Amazon eBay
A40-TB1-7	COMMON ALARM		Belt	Amazon eBay
A40-TB1-8	JUMPER WIRE		Belt	Amazon eBay
LF3000	Lube, Spin-On	1	Oil filter	Amazon eBay $76.00 NAPA $66.59

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	25%	20.0	5.2
Prime	50%	32.0	8.5
Prime	75%	45.0	11.9
Prime	100%	58.0	15.3
Standby	25%	21.0	5.5
Standby	50%	35.0	9.3
Standby	75%	50.0	13.1
Standby	100%	59.0	15.6

Available documents

Spec sheet — Cummins-installation-manual-DFAA-DFAB-DFAC-DFBC-DFBF-DFBD-DFBE-DFBF-DFCB-DFCC-DFCE-DFEB-DFEC-DFED-DFFA-DFFB-DFGA-DFGB-DFGC-DFJA-DFJB-DFJC-DFJD-DFLA-DFLB-DFLC-DFLD-DFLE-DFMB-DQAA-DQAB-DQBA-DQBB (Cummins/Onan)Spec sheet — cummins DFAC 250 kW 60Hz spec sheet (Cummins/Onan)Operator's manual — 960-0171 Cummins DFAB DFAC Operator's Manual (12-2012) (Cummins/Onan)Operator's manual — 960-0175 Cummins DFAB DFAC Operator's Manual (2-2013) (Cummins/Onan)Parts manual — 0932-0112 Onan Post-Sale Literature Index (07-1998) (Cummins/Onan)Parts manual — 0960-0204 (Cummins/Onan)Parts manual — 960-0260 Onan DFAA DFAB DFAC Parts Catalog (6-1997) (Cummins/Onan)Parts manual — 960-0293 Cummins DFAB DFAC Parts Manual (3-2003) (Cummins/Onan)Parts manual — 960-0298 Cummins DFAB DFAC Parts Manual (12-2012) (Cummins/Onan)Service manual — 9-3Service manual — 900-0519D Cummins DF- DQ Models Digital Paralleling (4-2005) (Cummins/Onan)Service manual — 960-0167 Cummins DFAB DFAC Operator's Manual (1-2003) (Cummins/Onan)Service manual — 960-0504 Onan DFxx series Generator Control Service Manual 04-1993 (Cummins/Onan)Service manual — 960-0507C Cummins DFAA thru DFMB DQAA Service Manual (2-2004) (Cummins/Onan)Service manual — 960-0519C Cummins DFAB DFB DFC DFG DFLC Series Service Manual (2-2004) (Cummins/Onan)Service manual — 960-0619D Cummins DFA DFB DFC DFE DFF DFG DFJ DFL DFM DQA DQB Installation (6-2003) (Cummins/Onan)Service manual — 960-0631B Cummins DFAB DFAC DFBF DFCC DFCE Installation Manual (2-2004) (Cummins/Onan)Service manual — 960-0634C Cummins DFAB DFBF DFCB DFCC DFCE Installation Manual (2-2004) (Cummins/Onan)Service manual — Cummins-3100-PowerCommand-DFAA-DFAB-DFAC-DFBC-DFBD-DFBE-DFBF-DFCB-DFCC-DFCE-DFEB-DFEC-DFED-DFFA-DFFB-DFGA-DFGB-DFGC-DFJA-DFJB-DFJC-DFJD-DFLA-DFLB-DFLC-DFLD-DFLE-DFMB-DQAA-DQAB-DQBB (Cummins/Onan)Service manual — DFxx Generator Set Service Manual PCC3100 (Cummins/Onan)Service manual — Detector Control Generator Set Service Manual (Cummins/Onan)

This page was generated from the 21 manufacturer documents above by automated extraction; every figure shown is copied from one of them. How the data is compiled.

Cummins/Onan DFAC Generator Set

Specifications

Engine

Filters for the Cummins/Onan LTA10

Same engine, other brands

Maintenance & consumables

Service intervals

Service specifications

Recommended fluids

Fault codes

Procedures

Voltage reconnection

Common questions

Troubleshooting

Fault codes

Symptoms & remedies

Repair guides

Parts

Fuel consumption

Available documents