HomeCummins/OnanCummins/Onan DD

Cummins/Onan DD Generator Set

The Cummins/Onan DD is a 30 kW (37.5 kVA) Diesel standby generator set powered by a Cummins/Onan DDA engine.

30 kW
Standby
2
Document types

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

Specifications

FuelDiesel
Standby power30 kW
Standby kVA37

Maintenance & consumables

for the Cummins/Onan DDA
ItemSpecCapacityPart #Interval
Fuel filter find
Oil filter find
Belt find
Coolant
Oil

Common questions

What is the power rating of the Cummins/Onan DD?

The Cummins/Onan DD is rated 30 kW standby (37.5 kVA).

What engine does the Cummins/Onan DD use?

The Cummins/Onan DD is powered by the Cummins/Onan DDA engine.

What fuel does the Cummins/Onan DD use?

The Cummins/Onan DD runs on Diesel.

Troubleshooting

14

Fault codes

CodeMeaningRemedy
OvercrankOvercrank fault lamp lights and engine stops cranking after approximately 75-seconds.Check for empty fuel tank, empty fuel filters, system leaks, or plugged fuel filters and fuel supply lines. Correct as required.
OvercrankEngine runs, shuts down, cranks for 75-seconds, cranking cycle stops, overcrank light on.Check for dirty fuel filters and replace if necessary (see MAINTENANCE section). Check for dirty or plugged air filters and replace if necessary (see MAINTENANCE section).
Low Oil PressureLow oil pressure shutdown.Check oil level and replenish if necessary. Contact Onan Distributor if oil level is correct.
High Engine TemperatureHigh engine temperature shutdown.
OverspeedOverspeed shutdown.
OverspeedOverspeed light on, no shutdown.
Low Oil PressureLow oil pressure light on, no shutdown.
High Engine TemperatureHigh engine temperature light on, no shutdown.

Symptoms & remedies

SymptomCauseRemedy
Engine stops cranking and fault lamp lights, after cranking approximately 75 seconds.Check for empty fuel tank, empty fuel filters, system leaks, or plugged fuel filters and fuel supply lines. Correct as required.
Fault lamp lights immediately after engine starts and unit shuts down.Indicates possible overspeed condition. Check the governor and throttle linkage for binding and freedom of movement. Contact an Onan Distributor or the engine manufacturer if linkage is not at fault.
Fault lamp lights and engine shuts down after running for a period.Check oil level and replenish if necessary. Contact Onan Distributor if oil level is correct. Check coolant level on radiator and heat exchanger sets and replenish if necessary. Check for slipping drive belts or for obstructions to the airflow. Check water flow valve on city water cooled sets and adjust if necessary. Contact an Onan Distributor or the engine manufacturer if none of the above.
Engine runs, shuts down and cranks for 75-seconds. Cranking cycle stops; fault lamp lights.Check for dirty fuel filters and replace if necessary (see MAINTENANCE section). Check for dirty or plugged air filters and replace if necessary (see MAINTENANCE section).
Fault lamp lights immediately after engine starts.Check for: Overspeed condition as engine starts.
Fault lamp lights, no fault exists.To check a no-fault condition, disconnect leads from TB11 terminals 29, 30 and 31. If fault lamp lights with leads disconnected, replace engine monitor board. Reconnect leads.

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

Parts

8
Part #DescriptionQtySystem
70048068Fuel, Secondary1Fuel filter Amazon eBay $20.99 PartsGeek
74048796Fuel, Secondary1Fuel filter Amazon eBay $26.25 PartsGeek
74348149Fuel, Secondary1Fuel filter Amazon eBay $30.71 PartsGeek
74355944Fuel1Fuel filter Amazon eBay $57.50 PartsGeek
FF117Fuel1Fuel filter Amazon eBay $199.00 PartsGeek
FF248Fuel, Secondary1Fuel filter Amazon eBay $8.99 PartsGeek
102206606Safety MessagesService part / kit PartsGeek
135-ABattery Group (Two 6-Volt, 135-A.H. [486 kC])Service part / kit PartsGeek

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

Operator's manual — 944-0121 Onan DDA Operator's Manual (2-1978) (Cummins/Onan)Operator's manual — 944-0122 Onan DDA DDB Genset Operator's manual (08-1982) (Cummins/Onan)Operator's manual — 944-0301 Onan DDA Operator's and Parts Manual (5-1975) (Cummins/Onan)Operator's manual — 944-0302 Onan DDB Operator's and Parts Manual (4-1974) (Cummins/Onan)Parts manual — 0932-0112 Onan Post-Sale Literature Index (07-1998) (Cummins/Onan)Parts manual — 944-0220 Onan DDB LDDB (spec A-E) Diesel Genset Parts manual (11-1982) (Cummins/Onan)