Specifications
| Fuel | Diesel |
|---|---|
| Frequency | 60.0 Hz |
| Standby power | 200 kW |
| Standby kVA | 250 |
| Oil capacity | 31.0 L |
| Alternator | Cummins/Onan 3 Phase 60 Hz YB |
| Phase | 3 |
| Power factor | 0.8 |
| Battery group | 8D |
| Battery voltage | 12 V |
| Battery quantity | 2 |
| Coolant capacity | 53 L |
| Dry weight | 2692 kg |
Engine
| Oil capacity | 31.0 L |
|---|---|
| Coolant capacity | 53.0 L |
| Aspiration | turbocharged |
| Rated speed | 1800 rpm |
Maintenance & consumables
for the Cummins/Onan NT-855-G2| Item | Spec | Capacity | Part # | Interval | |
|---|---|---|---|---|---|
| Air filter | Check and replace if necessary at specified intervals | — | 250 hr | find | |
| Fuel filter | Replace when dirty | — | 1000 hr | find | |
| Oil filter | As specified for Cummins engines | — | 250 hr | find | |
| Belt | Check tension and condition; replace if damaged | — | 50 hr | find | |
| Coolant | Ethylene glycol based coolant | 53.0 | — | 50 hr | |
| Coolant filter | Clean or replace as required. See Figure 7 for filter location and replacement procedure. | — | find | ||
| Oil | SAE 10W-30, 15W-40, or 20W-40 depending on temperature | 31.0 liters | — | 50 hr |
Common questions
What is the power rating of the Cummins/Onan DFP 250?
The Cummins/Onan DFP 250 is rated 200 kW standby (250.0 kVA).
What engine does the Cummins/Onan DFP 250 use?
The Cummins/Onan DFP 250 is powered by the Cummins/Onan NT-855-G2 engine.
What fuel does the Cummins/Onan DFP 250 use?
The Cummins/Onan DFP 250 runs on Diesel.
What is the oil capacity of the Cummins/Onan DFP 250?
The Cummins/Onan NT-855-G2 engine in the Cummins/Onan DFP 250 has an oil capacity of 31.0 liters.
What alternator does the Cummins/Onan DFP 250 use?
The Cummins/Onan DFP 250 uses a Cummins/Onan 3 Phase 60 Hz YB alternator.
Troubleshooting
24Fault codes
| Code | Meaning | Cause | Remedy |
|---|---|---|---|
| PRE HI ENGINE TEMP | *2. PRE HI ENGINE TEMP lamp lights. Engine continues to operate. | 2. Indicates engine has begun to overheat and engine temperature has risen to approximately 205°F (97°C). If generator is powering non-critical and critical loads and cannot be shutdown, use the following: a. Reduce load if possible by turning off non-critical loads. b. Check air inlets and outlets and remove any obstructions to airflow. c. Open doors or windows in generator area to increase ventilation. If engine can be stopped, follow procedure in step 3. | |
| HI ENG TEMP | *3. HI ENG TEMP lamp lights. Engine shuts down. | 3. Indicates engine has overheated (engine temperature has risen above 215°F/102°C) or coolant level is low (sets with coolant level sensor). Allow engine to cool down completely before proceeding with the following checks: a. Check coolant level and replenish if low. Look for possible coolant leakage points and repair if necessary. b. Check for obstructions to cooling airflow and correct as necessary. c. Check for a slipping fan belt and tighten if loose. d. Reset control and restart after locating and correcting problem. Contact an Onan Dealer or Distributor if none of the above. | |
| PRE LO OIL PRES | *4. PRE LO OIL PRES lamp lights. Engine continues to operate. | 4. Indicates engine oil pressure has dropped to 20 psi (138 kPa). If generator is powering critical loads and cannot be shut down, wait until next shutdown period and then follow step 5 procedure. If engine can be stopped, follow procedures in step 5. | |
| LO OIL PRES | *5. LO OIL PRES lamp lights. Engine shuts down NOTE: See also step 6. | 5. Indicates engine oil pressure has dropped to 14 psi (97 kPa). Check oil level, lines and filters. If oil system is okay but oil level is low, replenish. Reset control and restart. Contact an Onan Dealer or Distributor if oil pressure is not in the range of 50 to 70 psi (345 to 483 kPa). | |
| OVERCRANK | *6. OVERCRANK lamp lights and engine stops cranking. | ||
| FAULT 1 (red) | Undedicated fault. May be factory programmed as a shutdown or non-shutdown, and as a timed or non-timed (normally set for timed shutdown). | @ FAULT 1 (red) an undedicated fault. May be factory programmed as a shutdown or non-shutdown, and as a timed or non-timed (normally set for timed shutdown). | |
| FAULT 2 (red) | Same features as Fault 1 (normally set for timed shutdown). | @ FAULT 2 (red) same features as Fault 1 (normally set for timed shutdown). |
Symptoms & remedies
| Symptom | Cause | Remedy |
|---|---|---|
| *1. Green RUN lamp lights following engine start-up. | 1. Indicates all engine systems are normal. No corrective action required. | |
| Engine runs and then shuts down, OVERSPEED lamp lights. | Indicates engine has exceeded normal operating speed | Contact an Onan Dealer or Distributor for service. |
| SWITCH OFF lamp flashes. | Indicates Run/Stop/Remote switch is in the Stop position which will prevent automatic starting if an automatic transfer switch is used. Move the Run/Stop/Remote switch to the Remote position for automatic starting. | |
| Engine shuts down and LO OIL PRES lamp lights. | Indicates diesel fuel supply is running low. Check fuel supply and replenish as required. | |
| LO FUEL lamp lights. Engine continues to run. | Indicates engine has run out of fuel. Check fuel level and replenish as required. | |
| LO ENG TEMP lamp lights. | Indicates engine coolant heater is not operating or is not circulating coolant. Check for the following conditions: a. Coolant heater not connected to power supply. Check for blown fuse or disconnected heater cord and correct as required. b. Check for low coolant level and replenish if required. Look for possible coolant leakage points and repair as required. c. Contact an Onan Dealer or Distributor if none of the above. | |
| The FAULT 1 or FAULT 2 fault lamp lights. Engine shuts down immediately, engine runs for several seconds and then shuts down, or engine continues to run. | Indicates standard undesignated fault functions are programmed to shut down the set when a fault is sensed. Fault 1 is timed delayed while Fault 2 is immediate. The nature of the fault is an optional selection that is determined when the set installation is designed. The undesignated fault functions may also be programmed for non-shutdown or non-time delay. but will not start automatically or from a remote panel. (Note: The Run/Stop/Remote switch must be in the Remote position for automatic or remote starting). | |
| Fault lamp lights but no fault exists. | The monitor board or a sensor may be at fault. Contact an Onan Dealer or Distributor for service. | |
| Engine starts from generator control panel and restart. | Contact an Onan Dealer or Distributor if breaker trips after resetting. | |
| Engine will not crank. | Indicates possible fault with control or starting system. Check for the following conditions: a. Fault jam on. Correct fault and reset control. b. Poor battery cable connections. Clean the battery cable terminals and tighten all connections. c. Discharged or defective battery. Recharge or replace the battery. d. Contact an Onan Dealer or Distributor for assistance if none of the above. | |
| No AC output voltage. | Field breaker is tripped. Reset breaker. Contact an Onan Dealer or Distributor if voltage build up causes breaker to trip. | |
| Green RUN lamp does not light following engine start-up. | Indicates possible Start/Disconnect relay failure. Contact an Onan Dealer or Distributor for assistance. | |
| Engine has shut down because of critically low oil pressure | @ LO OIL PRES (red) indicates engine has shut down because of critically low oil pressure. | |
| Engine has shut down because of critically high temperature | @ Hi ENG TEMP (red) indicates engine has shut down because of critically high temperature. | |
| Engine has shut down because of excessive speed | @ OVERSPEED (red) indicates engine has shut down because of excessive speed. | |
| Starter has been locked out because of excessive cranking time | @ OVERCRANK (red) indicates the starter has been locked out because of excessive cranking time. | |
| Generator set is not in automatic start operation mode | @ SWITCH OFF (flashing red) indicates generator setis riot in automatic start operation mode. |
Fault codes and symptom→remedy steps extracted from this model’s service/owner documentation; verify against the official manual before servicing.
Parts
5| Part # | Description | Qty | System | |
|---|---|---|---|---|
| 8342-1 | LUBRICATION OIL FILTER | Oil filter | PartsGeek | |
| 903-0124 | NA | NA | Service part / kit | PartsGeek |
| 903-0204 | NA | NA | Service part / kit | PartsGeek |
| 903-0500 | NA | NA | Service part / kit | PartsGeek |
| 903-0604 | NA | NA | 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.