Home›Engines›Cummins/Onan NTA855-G4

Cummins/Onan NTA855-G4 Engine

The Cummins/Onan NTA855-G4 is a 14 L 6-cylinder turbocharged and water-to-air after-cooled engine rated at 1500 rpm. It powers generator sets from Cummins/Onan, including the 280DFCC, C380 D5 and NTA855. It holds 39 L (10.3 gal) of oil and 21 L (5.5 gal) of coolant.

Also known as: Cummins NTA855-G4, NTA855G4

Part of the Cummins/Onan NTA855 engine family — 17 variants share parts & fitment.

14.0 L

Displacement

Cylinders

1500 rpm

Rated speed

39.0 L

Oil capacity

On this pageSpecs Generator sets Maintenance FAQ Service intervals Torque & specs Fluids Fault codes Procedures Wiring

Engine specifications

Oil capacity	39.0 L
Coolant capacity	21.0 L
Displacement	14.0 L
Cylinders	6
Aspiration	Turbocharged and water-to-air after-cooled
Rated speed	1500 rpm

Generator sets powered by this engine

Cummins/Onan 280DFCCCummins/Onan C380 D5 Cummins/Onan NTA855

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

Maintenance schedule

Item	Spec	Capacity	Part #	Interval
Air filter			—
Fuel filter			—
Oil filter			—
Battery			—
Belt			—
Coolant			—
Oil			—
Spark plug			—

Pooled from every document that names this exact engine — confirm the interval and part number against your unit's serial number.

Service intervals

Item	Action	Hours	Months	Notes
Вентиляционные устройства генератора	Check	10 hr		10 часов / еженедельно
Весь агрегат	Test	10 hr		Включение минимум на час, предпочтительно с нагрузкой 50 %; 10 часов / еженедельно
Подключение вспомогательной клеммной коробки	Check	10 hr		10 часов / еженедельно
Уровень охладителя воды	Check	10 hr		10 часов / еженедельно
Уровень смазочного масла в двигателе	Check	10 hr		10 часов / еженедельно
Уровень топлива	Check	10 hr		10 часов / еженедельно
Уровень электролита в батарее	Check	10 hr		10 часов / еженедельно
Вентиляционный клапан топливного бака	Check	100 hr		100 часов / ежемесячно (положение отметки в таблице)
Все переключатели (в т.ч. двигателя)	Test	100 hr		100 часов / ежемесячно
Осадок в топливном баке	Drain	100 hr		100 часов / ежемесячно (положение отметки в таблице)
Отверстие и внутреннее пространство генератора	Clean	100 hr		Очистка сухим воздухом; 100 часов / ежемесячно
Соленоид подачи топлива	Check	100 hr		100 часов / ежемесячно
Уровень зарядки батареи гидрометром	Test	100 hr		100 часов / ежемесячно
Воздушный фильтр (у масляного – уровень масла)	Check	200 hr		200 часов / ежегодно
Все болты и гайки	Check	200 hr		Проверка и затягивание при необходимости; 200 часов / ежегодно
Все реле распределительной аппаратуры	Test	200 hr		200 часов / ежегодно
Кабельные контакты батареи	Clean	200 hr		200 часов / ежегодно; зачистка и смазка
Линии топлива, воздуха и выхлопная система на протечки	Check	200 hr		200 часов / ежегодно
Натяжение клиновидного ремня	Check	200 hr		200 часов / ежегодно
Плавкие предохранители и отключающие устройства	Check	200 hr		200 часов / ежегодно
Подшипники генератора	Lubricate	200 hr		200 часов / ежегодно
Проверка агрегата изготовителем	Inspect	200 hr		200 часов / ежегодно
Противовибрационные устройства	Check	200 hr		При наличии таковых; 200 часов / ежегодно
Смазочное масло	Change	200 hr		200 часов / ежегодно
Чистка всего агрегата и наружной поверхности панели управления	Clean	200 hr		200 часов / ежегодно
Чистота контакторов и контактов прерывателей	Check	200 hr		200 часов / ежегодно
Crankcase oil and filter	Change	250 hr	12 mo	Table 7-1. If genset used for prime power, change every 6 months or 250 hours. If standby, change every 12 months or 250 hours, whichever comes first.
valve clearance	Check	2000 hr		B-Series (4BT3.3): valve clearance checks not required for 2000 hours, twice the industry standard
engine overhaul	Other	20000 hr		QSK23-Series: expected life cycle to 20,000 hours before first overhaul
Содержание антифриза в системе охлаждения и фильтр	Check		6 mo	В таблице указано «Раз в 6 месяцев»

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	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	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
Other	Angular alignment maximum T.I.R.	.001	inch per inch of radius	center of shaft to indicator axis
Other	Глубина фундамента/цоколя и выступ за пределы агрегата	не менее 150	мм (6 дюймов)
Other	Минимальное расстояние от генератора до стены, резервуара или панели в машинном зале	1	м
Other	Нагрузка на грунт (ННГ) от агрегата, охладителя, топлива и фундамента	менее 9800	кг/м2 (2000 фунтов на кв. фут) или 96 кПа	требует проверки по местным нормам
Other	Площадь впускного отверстия воздуха для агрегатов с радиаторным охлаждением	в 1,5-2 раза больше площади радиатора
Other	Просвет выхлопной трубы глушителя	12	дюйма (300 мм)	двигатель QSK60
Other	Просвет выхлопной трубы глушителя	3	дюйма (76 мм)	двигатели B3.3, 4B, 6B
Other	Просвет выхлопной трубы глушителя	4	дюйма (100 мм)	двигатель 6C
Other	Просвет выхлопной трубы глушителя	6	дюйма (152 мм)	двигатели L, N, K19, V28
Other	Просвет выхлопной трубы глушителя	6×2	дюйма (152 мм)	двигатели K38, QSK30
Other	Просвет выхлопной трубы глушителя	8	дюйма (200 мм)	двигатели K50, QSK15
Other	Прочность бетона фундамента на сжатие (28 суток)	не менее 17200	кПа (2500 фунтов на кв. дюйм)
Pressure	Idle oil pressure shutdown limit (PCC)	12	psi (83 kPa)	idle
Pressure	Idle oil pressure warning limit (PCC)	15	psi (104 kPa)	idle
Pressure	Low oil pressure shutdown (Detector)	14	psi (97 kPA)
Pressure	Normal engine oil pressure (PCC)	35-50	psi (242-345 kPa)
Pressure	Oil pressure shutdown limit (PCC)	25	psi (172 kPa)
Pressure	Oil pressure warning limit (PCC)	30	psi (207 kPa)
Pressure	Pre-low oil pressure alarm (Detector)	20	psi (137 kPA)
Pressure	Предел обратного давления в выхлопной системе (большинство агрегатов Cummins)	3	дюйма рт. ст. (76 мм рт. ст.)	у последних моделей при максимальном потоке снижено до 2 дюймов рт. ст. (50 мм рт. ст.)
Resistance	Thermistor relay trip resistance	3000 ±500	ohms	thermistor chain resistance reaches
Resistance	Сопротивление электрода заземления при глухом занулении генераторной установки	не более 20	Ом	рекомендуется, независимо от системы защиты
Speed	Generator frequency/RPM (nameplate rating)	60 / 1800	hz / RPM	or 50 hz / 1500 RPM
Speed	Idle speed adjustment range	800 ±100	RPM	default value 800 RPM; adjustable only in idle mode
Speed	Overspeed shutdown (Detector)	1850 +50	r/min	50 hertz units
Speed	Overspeed shutdown (Detector)	2100 ±90	r/min	60 hertz units
Speed	Overspeed shutdown (PCC)	1800	rpm	@ 50 Hz
Speed	Overspeed shutdown (PCC)	2070	rpm	@ 60 Hz
Speed	PCC frequency adjust range	±5	percent of nominal
Temperature	Ambient temperature above which coolant heaters are recommended	40	°F (4°C)
Temperature	Engine coolant temperature (heat exchanger cooling)	165 to 195	°F (74 to 91 °C)	adjust flow to maintain while viewing water temperature gauge
Temperature	Engine coolant temperature (heat exchanger systems)	165 to 195	°F (74 to 91°C)	while viewing water temperature gauge
Temperature	High coolant temperature shutdown (PCC)	215	°F	primary
Temperature	High coolant temperature shutdown (PCC)	223	°F	standby
Temperature	High coolant temperature warning (PCC)	207	°F	primary
Temperature	High coolant temperature warning (PCC)	215	°F	standby
Temperature	High engine temperature shutdown (Detector)	222	°F (106° C)
Temperature	LOW COOLANT TEMP (Code 210) engine cold sensing threshold	70	°F (21 °C)	engine jacket water coolant temperature below
Temperature	Low coolant temperature warning sensing (PCC/Detector)	70	°F (21° C)
Temperature	NFPA 110 minimum engine jacket water coolant temperature	90	°F (32 °C)	maintained by coolant heaters
Temperature	NFPA 110 minimum maintained engine coolant temperature	90	°F (32°C)
Temperature	Pre-high engine temperature alarm (Detector)	215	°F (102° C)
Temperature	Допустимое повышение температуры в машинном зале при полной нагрузке	10-15	°C (18-27 °F)	если температура в зале превышает 40 °C – подавать аспирационный воздух извне или снизить нагрузку
Temperature	Расчетная температура окружающей среды для размеров машинного зала	40	°C
Temperature	Температура хладагента для облегчения пуска аварийного агрегата	выше 40	°C
Temperature	Температура эксплуатации батарей для оптимальной работы	15-25	°C
Torque	AC distribution panel 100 A main breaker lugs	50	in-lbs	#4 to 2/0 conductors, AL or CU
Torque	AC distribution panel 100A main breaker terminals	50	in-lbs	listed for #4 to 2/0 conductors, AL or CU
Torque	AC distribution panel ground bar	17	ft-lbs	#1 to 2/0 conductors, AL or CU
Torque	AC distribution panel neutral bus	21	ft-lbs	#5 to 300 KCMIL conductors, AL or CU
Torque	Oil drain plug	60-70	ft-lb (81-95 N•m)
Voltage	Megger test setting, 5001 thru 15000 VAC generator	5000	VDC	main stator minimum resistance 1000-200 meg; main rotor 1000-1000-5.0-1.0 meg
Voltage	Megger test setting, 600 VAC or less generator	500	VDC	main stator and main rotor minimum resistance 5.0-1.0 meg
Voltage	Megger test setting, 601 thru 5000 VAC generator	2500	VDC	main stator minimum resistance 400-50 meg; main rotor 5.0-1.0 meg
Voltage	PCC voltage adjust range	±5	percent of nominal

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	Notes
Coolant	Смесь воды и антифриза 50/50; низкосиликатный антифриз	Добавка Cummins DCA4 или эквивалент		Вода чистая, без хлоридов, сульфатов и кислот, с pH от 8,5 до 10,5; при заполнении холодной системы остается 6 (максимум 8) % дополнительной емкости для расширения
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).
Engine oil		Refer to the Cummins engine Operation and Maintenance Manual for lubricating oil recommendations/specifications		Add oil of the same API viscosity and brand when necessary. Do not operate below low mark or above high mark.
Fuel		Diesel fuel		Do not use zinc coated or copper fuel lines with diesel fuel. Fuel connection at the engine should be made with an approved flexible line.
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	No. 2 diesel fuel			Direct injection, number 2 diesel fuel; fuel filter; automatic electric fuel shutoff
Fuel	Дизельное топливо класса А1 или А2	BS 2869: Часть 1:1998 (класс А1); BS 2869: Часть 2:1998 (классы А2, С1, С2, D, E, F, G, H)		Топливо должно быть как можно более чистым, по возможности не содержать воды и загрязнений
Other	Природный газ	Наименьшая теплопроизводительность >30 МДж/Н·м3; плотность 0,7-0,9 кг/м3; метановое число >52; H2S >0,01 %; максимальная температура газа 50 °C	below 50°C	Требования к качеству газа для газовых двигателей; при несоответствии двигатель должен быть отключен

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	Engine is operating in idle mode.	Info	Normal indication. Engine governed at 800 RPM; oil pressure trip points lowered automatically.
102	EMERGENCY STOP	Local or remote Emergency Stop.	Shutdown	Pull button out or turn clockwise; move Run/Off/Auto switch to Off; press Reset. Reset only at PCC front panel.
200	LOW OIL PRESSURE	Engine oil pressure has dropped to an unacceptable level.	Warning	If powering critical loads, wait until next shutdown period then follow 201 procedure.
201	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 and restart; contact service center.
204	OIL PRES SENDER	Engine oil pressure sender is not functioning correctly.	Warning	Check that the engine oil pressure sender is properly connected. Contact service center.
210	LOW COOLANT TEMP	Coolant temperature at 70°F (21°C) or lower; coolant heater may not be operating.	Warning	Check coolant heater power supply/fuse/cord; check coolant level and replenish; repair leaks.
211	HIGH COOLANT TEMP	Engine has begun to overheat (215°F standby / 207°F primary).	Warning	Reduce load; check air inlets/outlets and remove obstructions.
212	HIGH COOLANT TEMP	Engine has overheated (223°F standby / 215°F primary) or coolant level is low.	Shutdown	Allow engine to cool; check coolant level; check cooling airflow; check fan belt; reset and restart.
213	COOLANT SENDER	Resistance of the coolant temperature sender is out of range.	Warning	Contact an authorized service center.
214	LOW COOLANT LVL	Engine coolant level has fallen below the trip point.	Warning	Allow engine to cool; check coolant level and replenish; look for leaks and repair; reset and restart.
215	LOW COOLANT LVL	Engine coolant level has fallen below the trip point.	Shutdown	Allow engine to cool; check coolant level and replenish; look for leaks and repair; reset and restart. Shutdown will not occur in Idle mode.
220	MAG PICKUP	Mag pickup speed indication not sensed or does not match generator set output frequency.	Shutdown	Restart and check RPM on the digital display. Contact service center.
221	FAIL TO CRANK	Possible fault with control or starting system.	Shutdown	Check battery cable connections; recharge or replace battery. Contact service center for starter and starting system.
222	OVERCRANK	Possible fuel system problem.	Shutdown	Check for empty fuel tank, leaks, or plugged fuel lines; check/replace fuel and air filters; reset and restart.
223	OVERSPEED	Engine has exceeded normal operating speed (2070 rpm @ 60 hz; 1800 rpm @ 50 hz).	Shutdown	Contact an authorized service center.
230	LOW DC VOLTAGE	Battery voltage is below 24 VDC.	Warning	Check battery charger fuse; recharge or replace battery; clean and tighten battery cable connections.
231	HIGH DC VOLTAGE	Battery voltage exceeds 32 VDC.	Warning	Contact an authorized service center.
232	WEAK BATTERY	Battery voltage drops below 60% of nominal for two seconds during starting.	Warning	See Warning message 230, LOW DC VOLTAGE.
240	LOW FUEL – DAY	Day tank fuel supply is running low.	Warning	Check fuel supply and replenish as required.
241	LOW FUEL	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	Contact an authorized service center.
251	EEPROM ERROR	PCC memory error; data corruption of noncritical operating parameters.	Warning	Contact an authorized service center.
252	EEPROM ERROR	PCC memory error; data corruption of noncritical operating parameters.	Warning	Contact an authorized service center.
260	CUSTOMER FAULT 1	Customer defined input closed to ground; response selectable.	Warning	Contact an authorized service center. Message is editable.
261	GROUND FAULT	Customer defined input closed to ground; response selectable.	Warning	Contact an authorized service center. Message is editable.
262	RUPTURE BASIN	Customer defined input closed to ground; response selectable.	Warning	Contact an authorized service center. Message is editable.
263	HIGH GEN TEMP	Customer defined input closed to ground; response selectable.	Warning	Contact an authorized service center. Message is editable.
301	HIGH AC VOLTAGE	One or more phase voltages exceeded 130% of nominal, or 110% of nominal for 10 seconds.	Shutdown	Contact an authorized service center.
303	LOW AC VOLTAGE	One or more phase voltages dropped below 85% of nominal for 10 seconds.	Shutdown	Contact an authorized service center.
313	UNDER FREQUENCY	Engine speed dropped below 90% of nominal for 10 seconds.	Shutdown	Contact an authorized service center. Load Dump signal initiated five seconds before shutdown.
320	OVERCURRENT	Generator output current exceeded 110% of rated for 60 seconds.	Warning	Contact an authorized service center.
321	OVERCURRENT	Generator output current exceeded 110% of rated and a PCC time/current calculation initiated an overcurrent shutdown.	Shutdown	Contact an authorized service center.
322	SHORT CIRCUIT	Generator output current exceeded 175% of rated.	Shutdown	Contact an authorized service center.
330	OVERLOAD	Three-phase power output exceeds 105% of standby (or 115% of prime) rating.	Warning	After five seconds Load Dump activated; after 60 seconds OVERLOAD warning activated. Contact service center.
335	REVERSE POWER	Improper CT or PT phasing (non-parallel units only).	Shutdown	Contact an authorized service center.
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

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.

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.

Ground Fault Relay Test diagnostic

Verify that the N-G Fault Indicator on the GFR is not lit; if lit, the neutral-to-ground bonding jumper circuit is open.
Move the control switch to the Run position.
Press the TEST switch on the ground fault relay.
Verify that the control panel warning message is displayed and the Fault Indicator (>I) on the GFR is lit.
Reset the control panel fault, which also resets the ground fault relay.

Megger and PI Test diagnostic

⚠ Medium-voltage, 601 to 15,000 volts, present special hazards of severe personal injury or death.

⚠ Windings of medium voltage generator sets must be dry before the generator is operated.

Tools: Megger, Grounding Cluster

Perform the Generator Set Grounding Procedure.
Disconnect plug J10 from voltage regulator output stage module and AC control input leads marked 4, 5, 6, 7 and 8.
If RTD option installed, ground all six RTD temperature leads (18 leads total).
Remove and separate neutral leads from generator load terminal marked N.
Connect megger between one stator phase and ground while grounding other two phases; conduct test.
Repeat for the other two phases.
Disconnect main rotor and voltage suppressor leads from terminals F1+ and F2- and isolate from ground.
Connect megger between one rotor lead and ground and conduct the test.

Fuel Pump Control AC Connections (240 VAC / 120 VAC Conversion) installation

Tools: Jumpers

To convert 240 VAC to 120 VAC: remove jumpers between TB1-6 and TB1-7; connect one between TB1-5 and TB1-6 and one between TB1-7 and TB1-8.
Move selector switch S103 on the control PCB to the up position for 120 V.
If equipped with a transformer, remove jumpers between H2 and H3; connect one between H1 and H3 and one between H2 and H4.
To convert 120 VAC to 240 VAC: remove jumpers between TB1-5/TB1-6 and TB1-7/TB1-8; connect two jumpers between TB1-6 and TB1-7.
Move selector switch S103 on the control PCB to the down position for 240 VAC.
Attach a tag to the control box indicating the supply voltage.
Terminals TB1-8 and TB1-5 are available for a 120 or 240 VAC electric fuel shutoff valve rated not more than 0.5 amps.

Fuel Pump Control AC Connections (240 VAC to 120 VAC) installation

⚠ Diesel fuel is highly combustible. Installation and service must be performed by trained and experienced persons in accordance with applicable codes.

Remove the two jumpers between terminals TB1-6 and TB1-7; connect one between TB1-5 and TB1-6 and the other between TB1-7 and TB1-8.
Move selector switch S103 on the control PCB to the up position for 120V.
If equipped with a transformer, remove jumpers between H2 and H3; connect one between H1 and H3 and the other between H2 and H4.
Attach a tag to the control box indicating the supply voltage.

Vibration Isolators Installation and Adjustment installation

⚠ Remove shipping screws (two) prior to genset operation. Genset operation with shipping screws in place will damage control components.

Tools: Leveling bolt, Lock nut, Shims or grout

Place the vibration isolators on the genset support structure; shim or grout so all isolator bases are within 0.25 inch (6 mm) elevation.
Loosen the side snubber lock nuts so the top plate is free to move; align top plate with base and springs.
Place the genset onto the isolators, aligning the skid's mounting with the threaded isolator hole.
Adjust leveling bolts until the set is level with a nominal clearance of 0.25 inch (6 mm) or greater between top plate and base.
Lock the leveling bolt in place with the lock nut; snubber nuts may remain loose for better isolation.
Model DFCE only: remove the two controller cabinet shipping screws before genset operation.

Vibration Isolators Installation and Adjustment Procedure installation

⚠ Remove shipping screws (two) prior to genset operation. Genset operation with shipping screws in place will damage control components.

Tools: Leveling bolt, Lock nut

Place vibration isolators on genset support structure; shim or grout bases within 0.25 inch (6 mm) elevation of each other on flat, level surface.
Loosen side snubber lock nuts so top plate is free to move vertically and horizontally.
Place genset onto isolators, aligning skid mounting with threaded isolator hole.
Adjust isolators using leveling bolt so set is level; nominal clearance of 0.25 inch (6 mm) or greater desired.
Adjust leveling bolts until set is level and sufficient clearance remains; lock leveling bolt with lock nut.
Snubber nuts may remain loose for better isolation.
Model DFCE only: remove the two controller cabinet shipping screws before operation.

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
		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.
115/200	Three Phase	Reconnectable
120/208	Three Phase	Reconnectable
120/240	Three Phase	Reconnectable
139/240	Three Phase	Reconnectable
277/480	Three Phase	Non-Reconnectable
277/480	Three Phase	Reconnectable
347/600	Three Phase	Non-Reconnectable

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

Parts cataloged across the Cummins/Onan NTA855 family

Part #	Description	Category
140-1346	Air Cleaner (Includes Element)	Air filter
140-2391	Element - Air Cleaner (Standard)	Air filter
140-2392	Element, Air Cleaner - Primary	Air filter
140-2393	Element, Air Cleaner - Safety	Air filter
511-0084	Belt, Charging Alternator	Belt
511-0160	Belt, Drive - V (Fan)	Belt
319-2236	Bracket, Mounting	Bracket
518-0548-58	Clamp, Hose	Clamp
130-3537	CE 1 130-3541 3318318 CE 1 4 501-0551 1 5 503-1467-07 1 503-0189 2 505-0022 1 502-0827	Coolant filter
130-3541	Filter, Water - w/Corrosion Inhibiting Chemical DCA4 (Pre-Charging)	Coolant filter
0300-4623-09	DFCB (600V)	Current transformer
0300-4623-10	DFCC (600V)	Current transformer
0300-4623-24	DFCB BR (0-480V)	Current transformer
0300-4623-27	DFCC BR (0-480V)	Current transformer
155-2287-02	Gasket, Flange (used with 155-2281 Elbow)	Gasket
501-0551	Line, Fuel - Flexible (Bypass line)	Hose
503-1467-07	Hose, Rubber (3/4" ID x 33" LG) Radiator to Filter Housing	Hose
503-1679-02	Hose, Rubber - Upper	Hose
505-1414-01	Hose, Rubber - Lower	Hose
122-0526	Element, Filter	Oil filter
122-0755	Lube & Bypass Filter (Latest Style Used In Engine Manufacturing)	Oil filter
LF3000	Lube, Spin-On	Oil filter
100-1359	Engine, Replacement (Cummins NTA855G)	Service part / kit
102-1335	Plug, Oil Drain	Service part / kit
305-0813-02	CUMMINS battery charger 208VAC/24VDC/10A	Service part / kit
307-2621-02	Relay, Start Solenoid (K4)	Service part / kit
309-0437	(222"F)	Service part / kit
504-0011	Valve, Shutoff (1/2”)	Service part / kit
505-0019	Bushing, Pipe - Reducer 1/2” to 3/8”, DFBF (1/2” to 3/8”) 505-0131 DFCB, DFCC, DFCE (3/4” to 3/8”)	Service part / kit
505-0100	Nipple, Pipe - Close (1/2”)	Service part / kit
526-0029	*Washer, Flat (1/2")	Service part / kit
526-0219	Washer, Flat (1/2)	Service part / kit
800-0048	Screw, Cap - Hex Head (3/8-16 x 3/4”)	Service part / kit
800-0092	Screw, Cap - Hex Head (1/2-13 x 1.5)	Service part / kit
850-0050	Washer, Lock - Spring (3/8”)	Service part / kit
870-0212	Nut, Locking (1/4-20)	Service part / kit
903-0124	NA	Service part / kit
903-0204	NA	Service part / kit
903-0500	NA	Service part / kit
903-0604	NA	Service part / kit
E204747	Coolant heater 240/480V 6420W 1PH	Service part / kit
508-0292	Washer, Sealing - Copper	Seal
151-0411	Pickup, Magnetic	Sensor
193-0244	Sender, Oil Pressure (E1)	Sensor
193-0375	Sender, Coolant	Sensor
193-0432	Sender, Oil Temperature (S2 Engine Block, E4 Oil Pan)	Sensor
309-0179	Switch, High Water Temperature (Standard Part) Side Mounted On Water Outlet Housing	Sensor
309-0269	Sender, Temperature-Lo Engine	Sensor
333-0407	Switch, Pressure - Oil, 14# PSI (SHUTDOWN) With Dual Terminals	Sensor
960-0504	PCC Control Service Manual	Service manual
960-0507	Detector Control Service Manual	Service manual

Parts cataloged across all variants of this engine family — verify the exact part fits your specific variant and serial number before ordering.

Common questions

What is the oil capacity of the Cummins/Onan NTA855-G4?

The Cummins/Onan NTA855-G4 engine has an oil capacity of 39.0 liters.

What is the displacement of the Cummins/Onan NTA855-G4?

The Cummins/Onan NTA855-G4 has a displacement of 14.0 liters with 6 cylinders.

Which generators use the Cummins/Onan NTA855-G4 engine?

The Cummins/Onan NTA855-G4 powers 3 generator set(s), including Cummins/Onan 280DFCC, Cummins/Onan C380 D5, Cummins/Onan NTA855.