Cummins/Onan 500 DFFB Generator Set

⚠ Ignition of explosive battery gases can cause severe personal injury. Do not smoke or allow arc-producing devices around the battery area.

⚠ Do not disconnect battery cables while the generator set is cranking or running.

1. Use two 12-volt batteries for a normal installation.
2. Connect the batteries in series: negative post of the first battery to the positive post of the second battery.
3. Connect the negative (-) battery cable last to reduce the risk of arcing.
4. If an automatic transfer switch is not used or has no built-in charge circuit, connect a float charger to the batteries.

1. Check ventilation and exhaust systems.
2. Check all mechanical connections.
3. Fill the coolant, lubrication and fuel systems.
4. Prime the lubrication and fuel systems.
5. Check the fuel system for leaks.
6. Check the lubrication system for leaks.
7. Verify all electrical connections are secure and wiring is complete.
8. Check load cables are properly connected to transfer switch or circuit breaker panel.

1. Place the isolators on the genset support structure.
2. Shim or grout isolators so all isolator bases are within 0.25 inch (6 mm) elevation of each other; surface must be flat.
3. Loosen the side snubber lock nuts so the top plate is free to move vertically and horizontally.
4. Place the genset onto the isolators, aligning the skid's mounting with the threaded isolator hole.
5. Insert the leveling bolt through the skid and into the isolator; lock nut threaded up toward the bolt head.
6. Adjust the leveling bolt for a nominal clearance of 0.25 inch (6 mm) or greater between top plate and base.
7. Adjust leveling bolts until the set is level and sufficient clearance remains; lock leveling bolt with lock nut.
8. Snubber nuts may remain loose to provide better isolation.

⚠ Diesel injection system tolerances are precise; keep fuel clean and free of water to avoid damage to injection pump and nozzles.

1. Remove each fuel filter and fill with clean fuel.
2. Put a light coat of fuel on the sealing gasket.
3. Install and tighten by hand until the gasket just touches the filter head.
4. Tighten the filter an additional one-half to three-fourths turn.

Tools: hand or motor driven priming pump with pressure gauge, torque wrench

1. Remove oil inlet line from turbocharger housing; fill bearing housing with clean engine lubricating oil; replace line and secure.
2. Fill crankcase to L (low) mark on dipstick.
3. Connect a hand or motor driven priming pump with pressure gauge from clean oil source to the plug boss in the filter housing.
4. Prime until a 30 psi (207 kPa) pressure is obtained.
5. Disconnect wire from fuel solenoid valve.
6. On the engine control panel, depress the RUN switch to crank the engine, maintaining 15 psi (103 kPa) oil priming pressure for 15 seconds at the filter head priming port.
7. Stop engine cranking, remove external priming equipment, reinstall plug in filter housing and torque to 15 to 20 ft lb (20 to 27 N·m).
8. Reconnect wire to fuel solenoid valve.
9. Complete oil fill to H (high) mark on dipstick.

⚠ High AC voltages present hazard of severe personal injury or death; during a no-load test there should be no AC output current readings.

⚠ Inhalation of exhaust gases can result in severe personal injury or death; shut down and repair leaks immediately.

⚠ Leaking fuel creates fire or explosion hazard.

Tools: remote voltmeter (on sets without AC meters)

1. Confirm that Field Circuit Breaker is at Reset position.
2. Place the Lamp Test/Reset/Panel Lamp switch at LAMP TEST; all indicator lamps will illuminate; then place switch at PANEL LAMP.
3. Place the Run/Stop/Remote switch at RUN; starter cranks and engine should start within a few seconds.
4. Check oil pressure gauge reads 40 to 60 psi (275 to 414 kPa) at operating temperature.
5. Check water temperature gauge reads 165° to 195°F (74° to 91°C).
6. Check battery gauge reads approximately 24 to 28 volts while set is running.
7. Check generator frequency meter is stable and reads nameplate rating (50 or 60 Hz).
8. Check AC amperes: zero at no-load; all three phases approximately the same under load; no line current exceeds nameplate rating.
9. Check line-to-line AC voltage at full load equals nameplate rating; adjust Voltage Adjust rheostat as necessary.
10. Inspect the entire exhaust system visually and audibly for leaks.
11. Inspect fuel supply lines, filters, and fittings for leaks; check flexible sections for cuts, cracks and abrasions.
12. Stop the set by moving Run/Stop/Remote switch to STOP.