CUMMINS C20N6HC (01) PDF Document

The safety styles and symbols found throughout the manual for your CUMMINS C20N6HC indicate potentially hazardous conditions to the operator, service personnel, or equipment.

DANGER: Indicates a hazardous situation that, if not avoided, will result in death or serious injury.

WARNING: Indicates a hazardous situation that, if not avoided, could result in death or serious injury.

CAUTION: Indicates a hazardous situation that, if not avoided, could result in minor or moderate injury.

NOTICE: Indicates information considered important, but not hazard-related (e.g., messages relating to property damage).

Always follow these general safety precautions when operating or servicing your CUMMINS C20N6HC:

Hazardous Voltage: Contact with high voltages can cause severe electrical shock, burns, or death. Ensure only a trained and experienced electrician makes electrical output connections.

Electrical Generating Equipment: Faulty equipment can cause severe injury or death. It must be installed, certified, and operated by trained and experienced persons according to instructions and codes.

Moving Parts: Moving parts can cause severe personal injury. Use extreme caution and ensure all guards are properly fastened.

Toxic Hazard: Used engine oils may cause cancer or reproductive toxicity. Do not ingest, breathe fumes, or contact used oil. Wear protective gloves and a face guard.

Incorrect Operation: Do not operate the equipment when fatigued or after consuming alcohol or drugs. Only trained personnel should perform service.

Toxic Gases: Substances in exhaust gases can cause cancer or reproductive toxicity. Do not breathe in or come into contact with exhaust gases.

High Noise Level: Generator sets in operation emit noise that can cause hearing damage. Wear appropriate ear protection.

Hot Surfaces: Contact with hot surfaces can cause severe burns. The unit should be installed to minimize contact risk. Wear appropriate PPE when working on hot equipment.

Combustible Liquid: Ignition of combustible liquids is a fire or explosion hazard. Do not store fuel, cleaners, or oil near the generator set.

Combustible Gases: Generator sets in operation have combustible gases under pressure. Wear eye and ear protection and do not operate with any doors open.

Fire Hazard: Materials drawn into the generator set, as well as accumulated grease and oil, are a fire hazard. Keep the generator set and surrounding area clean and free from obstructions.

Automated Machinery: Accidental or remote starting can cause severe personal injury or death. The generator set must be off and locked out when panels are removed. Isolate auxiliary supplies and disconnect battery cables (negative first).

Fire Extinguishers: Keep multi-type ABC fire extinguishers close by.

Access Doors: Before maintenance, ensure service access doors are secured open.

Do Not Step on Unit: Stepping on the generator set can cause damage leading to electrical shorts or leaks. Do not step on the generator set.

To prevent severe personal injury or death from moving parts on your CUMMINS C20N6HC, follow these precautions:

• Keep hands, clothing, and jewelry away from moving parts.

• Before starting work, disconnect the battery charger from its AC source, then disconnect the starting batteries using an insulated wrench, negative (–) cable first, to prevent accidental starting.

• Ensure all fasteners on the generator set are secure. Tighten supports and clamps, and keep guards in position over fans, drive belts, etc.

• Do not wear loose clothing or jewelry near moving parts or while working on electrical equipment, as they can become caught.

• If adjustments must be made while the unit is running, use extreme caution around hot manifolds and moving parts.

Voltages and currents from the CUMMINS C20N6HC present a shock hazard that can cause severe burns or death. Contact with energized circuits of 50 Volts AC or 75 Volts DC or higher can be fatal. Follow these guidelines:

Guidelines for De-energized Electrical Systems:

• Use proper PPE. Do not wear jewelry and remove conductive items from pockets to prevent short circuits.

• De-energize and lockout/tagout electrical systems before working on them to prevent unexpected start-up or release of stored energy.

• De-energize and lockout/tagout all circuits before removing protective shields or making measurements.

• Follow all applicable regional electrical and safety codes.

Guidelines for Energized Electrical Systems:

• Do not tamper with or bypass interlocks unless authorized.

• Understand and assess the risks. Use proper PPE, do not wear jewelry, and remove conductive items from pockets.

• Ensure an accompanying person who can perform a rescue is nearby.

Fire, explosion, and personal injury or death can result from improper practices with fuel and fumes. Follow these precautions for your CUMMINS C20N6HC:

• Do not permit any flame, cigarette, pilot light, spark, arcing equipment, or other ignition source near the generator set or fuel system.

• Fuel lines must be adequately secured and free of leaks. Use an approved flexible line for the fuel connection at the engine.

• Ensure all fuel supplies have a positive shutoff valve.

• Ensure the battery area is well-ventilated before servicing near it, as lead-acid batteries emit highly explosive hydrogen gas.

• Natural gas is lighter than air and may gather under covered areas.

• Do not operate the generator set in a flammable or explosive environment unless it is equipped with an automatic safety device to block the air intake and stop the engine.

Engine-driven generator sets like the CUMMINS C20N6HC produce harmful levels of carbon monoxide (CO), which is an odorless, colorless, tasteless, and non-irritating gas that can cause injury or kill you. To protect yourself and others from CO poisoning:

• It is recommended that reliable, approved, and operable CO detector alarms are installed in proper locations in the home as specified by their manufacturer.

• Locate the generator set in an area where there are no windows, doors, or other access points into the home.

• Make sure all CO detectors are installed and working properly.

• Pay attention for signs of CO poisoning, which include eye irritation, dizziness, headaches, fatigue, inability to think clearly, vomiting, seizures, and collapse.

• Check the exhaust system for corrosion, obstruction, and leaks every time you start the generator set and every eight hours when you run it continuously.

To perform the test procedures in the service manual for your CUMMINS C20N6HC, the following test equipment must be available:

• True RMS (Root Mean Square) meter for accurate measurement of small AC and DC voltages

• Grounding wrist strap to prevent circuit board damage due to electrostatic discharge (ESD)

• Wheatstone bridge or digital ohmmeter

• Load bank

• Megger or insulation resistance meter

The cold weather starting and operating requirements for the CUMMINS C20N6HC are based on ambient temperature:

The engine specifications for the CUMMINS C20N6HC are as follows:

The clock needs to be reset whenever battery power is lost or disconnected. To set up the generator set clock for the current date and time:

1. From the Main screen, select Menu.

2. Use the arrow keys to highlight Clock. Select the Enter key.

3. Use the arrow keys to set the time and date.

4. Select the Next key to go to the Daylight Savings screen.

5. Use the arrow keys to enable/disable Daylight Savings. If enabling, select the Next key to highlight the Offset field.

6. Use the arrow keys and Next key to set the offset value for Daylight Savings time.

7. Select the Next key to go to the screen that is used to set up when Daylight Savings should start. Use the arrow keys and Next key to set Month (1 – 12), Week (0 – 5), Day (Sun – Sat) and Hour (12AM – 12PM).

8. Select the Next key to go the screen that is used to set up when Daylight Savings should end. Use the arrow keys and Next key to set Month (1 – 12), Week (0 – 5), Day (Sun – Sat) and Hour (12AM – 12PM).

9. Keep selecting the Back button to save the settings and return to the main screen.

To set up the exercise function on your CUMMINS C20N6HC:

1. From the Main screen, select Menu.

2. Use the arrow keys to highlight Exercise. Select the Enter key. (Note: The date and time must be set first).

3. Use the arrow keys to enable or disable the Crank Exercise feature. Select the Next key to go to the Exercise Time field.

4. Use the arrow keys to set how long the generator set will exercise (from 1 to 20 minutes). Select the Next key to go to the Exercise field. The Exercise Sched screen appears.

5. Use the arrow keys to set how often the generator set will exercise. The frequency selections are:

• Weekly: will exercise the generator set on every occurrence of the selected day

• Bimonthly: will exercise the generator set on the first and third occurrence of the selected day every month

• Monthly: will exercise the generator set on the first occurrence of the selected day every month

• Never: will never exercise the generator set

Select the Next key to go to the date and time fields.

6. Use the arrow keys to set the day and time the generator set will be exercised. Select the Next key to highlight the Exercise Now field.

7. Select either arrow key to start the Exercise Now function immediately.

8. Keep selecting the Back button to save the settings and return to the Main screen.

To adjust the brightness and contrast of the display on your CUMMINS C20N6HC:

1. From the Main screen, select Menu.

2. Use the arrow keys to highlight Display Setup. Select the Enter key.

3. Use the arrow keys to set brightness and contrast for the display.

4. Keep selecting the Back button to save the settings and return to the Main screen.

The automatic load management feature on the CUMMINS C20N6HC automatically adds or removes specific electrical loads to prevent the generator from being overloaded. This requires load management devices to be wired to the generator set load management outputs.

When the generator starts, the control disconnects all managed loads. Once the transfer switch moves to generator power, the control evaluates the total load. If the total load is below a set point (80% of rated), the control will sequentially add the highest priority managed load every three minutes, as long as adding the next load doesn’t exceed the set point. The load priorities are:

• Priority #1: load control 1

• Priority #2: load control 2

• Priority #3: load control 3

• Priority #4: load control 4

If the load on the generator exceeds 95% of its rating, the control will begin disconnecting the lowest priority managed loads in sequence every second until the load is below 95%.

For an auto start sequence to execute on your CUMMINS C20N6HC, Standby Mode must be enabled. If utility power is not available (power outage), the following sequence will occur:

1. The generator set starts.

2. After the generator set reaches rated voltage and frequency, the transfer switch transfers the building load to the generator set.

3. When utility power is restored, the sequence to transfer the building load back to the utility begins.

4. The generator set continues to run and waits for utility power to stabilize.

5. When utility power is stable for 5 minutes, the transfer switch connects the building load back to utility power.

6. The generator set runs for an additional 5 minutes to cool down and then shuts off.

7. Normal operation resumes.

The following steps will be executed when Manual Start is used at the local display of your CUMMINS C20N6HC:

1. If you do not want the Automatic Transfer Switch (ATS) to transfer load to the generator set, open the generator set mounted circuit breaker.

2. From the Main screen, select the START key.

3. A second screen appears notifying you that Standby will be disabled. Select the START key again to start the generator set.

4. After the generator set reaches rated voltage and frequency, the transfer switch transfers the building load to the generator set (unless the circuit breaker is “off”).

To manually stop your CUMMINS C20N6HC from the local display:

1. Press the red STOP button on the local display. The generator set will stop immediately and the building load will be transferred to the utility. Pressing the red STOP button will cause both Remote and Standby Modes to be disabled.

2. For normal operation to resume, Standby will need to be enabled again.

Before any work is carried out, the generator set must be properly immobilized to be considered safe. Follow this procedure:

1. Press the generator set’s red STOP button on the local display to stop the generator set. Allow it to thoroughly cool to the touch.

2. Thoroughly ventilate the generator set before disconnecting any leads.

3. Turn off and disconnect any AC powered devices at the generator set, such as oil heater, battery heater, and battery charger before disconnecting the battery cables.

4. De-energize and lock off any utility power to the generator set.

5. Turn off the fuel supply to the generator set.

6. Disconnect the negative (–) cable from the battery and secure it from contacting the battery terminals to prevent accidental starting or electrical arcing.

7. Place warning notices at each of the above locations that state, “Maintenance in Progress – Immobilized for Safe Working.”

The cover of the CUMMINS C20N6HC is designed to latch securely in the “up” position to prevent accidental closure.

• To open: Lift the cover until the hinge pin drops into the hinge pin slot. Test that the cover is secure by gently pressing down on it.

• To close: Lift up on the cover while pressing upward on the hinge pin and slide the pin upwards out of the hinge pin slot. Carefully push the cover downward and let go of the hinge pin, allowing it to ride along the hinge until the cover is closed.

Perform all service at the time period indicated, or after the number of operating hours indicated, whichever comes first. For extreme operating conditions, service intervals should be reduced.

¹ Perform sooner if engine performance deteriorates.

² Perform more often when operating in high temperature conditions.

³ Check daily during power outages, or monthly without power outages.

⁴ Perform more often when operating in dusty conditions.

⁵ See the automatic transfer switch manual for testing of load transfer.

⁶ Must be performed by a qualified service technician (authorized Cummins Inc. service provider).

⁷ Clean slip rings with an approved tool, 3M Scotch Bright pads Maroon (Grit Equiv. 360-400) OR 3M Three-M-ite 400 grit cloth.

Check the engine oil level when the generator set is not running and is out of Remote mode. Overfilling can cause foaming, and underfilling can cause loss of oil pressure.

1. Make sure that the generator set has not been running for approximately five minutes.

2. Clean off the area surrounding the dipstick port to prevent debris from entering the engine.

3. Pull out the dipstick and wipe it clean.

4. Reinsert and fully seat the dipstick.

5. Remove the dipstick and check the oil level. It should be between the High and Low marks.

6. Reinsert and fully seat the dipstick.

If the level is incorrect, oil must be added or drained.

This service should be performed by qualified technicians. Change the oil and filter when the generator set is not running and is out of Remote mode.

1. Open the generator set’s circuit breaker.

2. Manually start the generator set.

3. Allow the set to run for 2 to 5 minutes to warm the engine oil.

4. Make sure the generator set is shut down and disabled (press STOP, cool down, disconnect battery charger, disconnect negative battery cable).

5. Remove the access panels to get to the drain hose.

6. Open the oil drain cap at the end of the hose and the drain valve at the engine to release oil into an appropriate container.

7. Close the drain valve and drain cap on the hose.

8. Wipe the oil drain cap clean.

9. Place a container below the oil filter.

10. Remove the oil filter by turning it counterclockwise.

11. Remove the old gasket if it remains on the engine.

12. Clean the filter mounting surface on the engine block.

13. Apply a thin film of clean oil to the gasket of the new filter.

14. Install the new filter until the gasket touches the block, then turn it an additional 1/2 to 3/4 turn. Do not over-tighten.

15. Remove the container.

16. Add the appropriate amount of oil.

17. Check the engine oil level and adjust as needed.

18. Clean any spilled oil.

19. Ensure the generator set breaker is still open.

20. Reconnect battery cables (positive first) and battery charger.

21. Reconnect oil heater AC power if applicable.

22. Operate the generator set with no load for 5 minutes to check for leaks.

23. Shut down the generator set, wait 5 minutes, and confirm the correct oil level.

24. Repair any identified leaks.

25. Dispose of used oil and filter according to local regulations.

26. Re-install access panels.

27. Restore original generator set settings.

28. Close the generator set breaker.

This procedure should be performed by a qualified technician.

1. Shut down and disable the generator set (press STOP, disconnect battery charger, disconnect battery cables).

2. Open the hood and remove the control, intake air, and exhaust panels.

3. Remove the oil filter access panel, oil cooler bolts (move cooler aside), and starter access panel.

4. Remove the valve covers from both cylinders.

5. Using a socket on the flywheel bolt, rotate the engine clockwise until the intake valve closes on one cylinder.

6. Rotate the crankshaft another 45–135° clockwise. The rocker arm should not move.

7. Check the valve clearance with a feeler gauge. If out of specification, adjust to the lower specification limit.

8. To adjust:

a. Loosen the locking nut while holding it with a spanner wrench.

b. Turn the adjusting nut with a hex wrench to adjust the clearance.

c. When desired clearance is reached, hold the adjusting nut and tighten the locking nut to 14–18 Nm (10.3–13.3 ft-lb).

9. Rotate the engine clockwise until the exhaust valve closes and the intake valve begins to open.

10. Check and adjust the exhaust valve clearance to its lower specification limit.

11. Repeat steps 5 through 10 for the remaining cylinder.

12. Assemble the valve cover with a new gasket. Torque bolts to 8–12 Nm (71–106 in-lb) in the specified sequence.

13. Reinstall all panels and components, reconnect the battery, and restore power and settings.

Cummins Inc. does not recommend cleaning paper-type air cleaner elements. Follow these steps to replace it:

Removal:

1. Ensure the generator set is shut down and disabled (press STOP, disconnect battery charger, disconnect negative battery cable).

2. Remove the access cover to get to the air cleaner housing.

3. Wipe any debris from the air cleaner housing.

4. Remove the two M6 pan head screws.

5. Remove the top of the air cleaner housing, which contains the element. Ensure no debris enters the base of the housing or the engine intake.

6. Pull up on the fastener end of the housing top and slide it back to release it from the tabs.

7. Remove the dirty cleaner element and dispose of it according to local regulations.

Installation:

1. Clean the gasket surface on the air cleaner housing base.

2. Place the new air cleaner element in the housing top.

3. Push the element into the housing until its gasket is fully seated.

4. Place the slots on the top over the tabs on the housing bottom, and rotate the cover to the seated position.

5. Install the two pan head screws. Torque to 2.3 – 3.0 ft-lb (3.2 – 4 Nm).

6. Re-install the access panel. Torque screws to 3.5 – 5.0 ft-lb (5.0 – 6.6 Nm).

7. Reconnect the battery and restore original settings.

A complete system test is recommended every 200 hours or every 2 years to verify the electrical system is working properly. Only authorized and qualified technicians should perform this test.

1. Before starting:

• Check the oil level.

• Verify that fuel related components outside of the generator set are open.

• Review the checklist in the installation manual.

2. Place the generator set in Standby mode.

3. Switch the main utility disconnect from the ON to the OFF position.

4. Make sure the following occurs:

a. The generator set starts.

b. After the generator set starts and stabilizes, the load is transferred from the utility to the generator set.

5. Switch the main utility disconnect from the OFF to the ON position.

6. Make sure the following occurs:

a. After approximately 5 minutes, the load is transferred back to the utility.

b. Once the transfer switch is connected to utility power, after approximately 5 minutes, the generator set stops.

If the test fails, contact your authorized Cummins service provider.

Logic: The generator set control receives a start signal either from the ATS with Standby enabled, or from a remote device with Remote enabled.

Possible Causes:

• Shorted harness connection

• Faulty ATS signal or relay and “Standby” is enabled

• Remote enabled and start command sent from a remote device

Diagnosis and Repair:

1. If Remote is enabled, a remote start signal may be coming from a monitoring system or remote display. Discuss this functionality with the customer.

2. Disconnect the ATS start signal at customer connection TB6 (Remote Start Input).

3. Measure for continuity to GND of both TB6 and customer wiring.

4. If present, inspect the wiring from the ATS for a short to GND and refer to the appropriate RA series ATS owner manual for diagnosis.

5. If there is continuity of TB6 to GND, locate the short to ground in the harness, and repair or replace it.

Logic: The generator set control received a stop signal.

Possible Causes:

• Loss of the Remote Start command

• A remote stop command from a remote monitoring device

• Low battery voltage

Diagnosis and Repair:

1. Check the last fault recorded. If it has not been repaired, troubleshoot that fault. If it has, continue.

2. A remote stop signal may have come from the Remote Monitoring System or a remote display. Discuss this functionality with the customer.

3. Verify that battery voltage is acceptable (minimum 8V for display operation).

4. Measure battery voltage while attempting to start. Recharge or replace the battery if the voltage drops below 8 VDC.

5. Test and service the generator set battery charger.

6. Check electrolyte level and hydrometer reading in maintenance-type batteries. Replace electrolyte or battery if necessary.

7. Check the ATS start signal circuit for an open circuit.

8. Verify pin and socket conditions for P1 and P2 connectors on the control board for corrosion or damage.

Logic: The control receives a start command but does not crank.

Possible Causes:

• Low or no battery voltage

• Poor battery connection

• Faulty battery

• Open harness connection

• Faulty control board

• Faulty starter

Diagnosis and Repair:

1. Attempt to replicate the fault.

2. Measure battery voltage at the battery, generator set, and connector P1. Reconnect, clean, repair, or replace connections as necessary.

3. Measure battery voltage at the generator set while starting. Recharge or replace the battery if voltage drops below 8 VDC. Service the battery charger.

4. Inspect the starter: Verify B+ at the starter’s positive terminal and at the starter solenoid terminal while attempting to crank. If the battery is good, replace the faulty starter.

5. Inspect control board pins P1 and P2 for damage or corrosion. Clean, repair, or replace the control board if necessary.

6. Ensure P1 and P2 connectors are fully seated.

Logic: The generator set control detects a continuous ground (3 seconds or more) for the oil pressure input, indicating low oil pressure.

Possible Causes:

• Low/high oil level

• Faulty oil pressure switch

• Faulty oil pressure relief valve in engine

• Faulty harness (unintentional ground)

• Faulty oil pump

Diagnosis and Repair:

1. Check and correct the oil level.

2. Disconnect the oil pressure switch plug and check for continuity from P1-6 to GND. If continuity exists, repair the short in the harness.

3. Verify switch operation: check for continuity across the switch when not running (should be continuity) and for an open circuit when running. Replace the switch if it’s not working correctly.

4. Measure oil pressure with a mechanical gauge. If pressure is low, the engine may need to be replaced.

Logic: The generator set control did not sense alternator quad winding frequency after a full cycle crank (3 crank attempts of 30 seconds with 15 seconds rest in between).

Possible Causes:

• No fuel

• Incorrect air/fuel mixture

• Faulty wiring, starter, ignition, or battery

• Incorrect oil viscosity

• Iced or corroded brushes/slip rings

• Slow cranking speed

Diagnosis and Repair:

1. Verify the fuel valve is open.

2. Check for proper DC voltage at the fuel solenoid during cranking.

3. Check fuel supply pressure.

4. Check engine ignition system (spark plugs, leads, magneto).

5. Check for correct oil type for ambient temperature.

6. Check battery and connections.

7. Measure field, quadrature, and main winding resistance.

Logic:

• Instantaneous Fault: AC voltage S1-S2 is greater than 300 VAC.

• Delayed Fault: AC voltage line-to-line is greater than 268 VAC but less than 300 VAC for 3 continuous seconds.

Possible Causes:

• Generator set loads

• Wire connections

• Alternator windings

• Faulty voltage regulator

• Sticking governor linkage

Diagnosis and Repair:

1. Check the last recorded fault.

2. Measure AC voltage at the circuit breaker and pins P1-34/P1-35.

3. Verify AC frequency on the display and with a DMM. If they don’t match, replace the control board.

4. Cycle loads to see if a particular load causes the fault.

5. Check for clean slip rings and good brushes, and measure winding resistances.

Logic: AC voltage (240 line-to-line) is less than 216 VAC for 5 continuous seconds.

Possible Causes:

• Generator set loads / overload

• Wire connections

• Alternator windings

• Governor issue

Diagnosis and Repair:

1. Check the last fault recorded.

2. Measure AC voltage at the circuit breaker and pins P1-34/P1-35.

3. Cycle loads to determine if a particular load is causing the fault. Diagnose faulty loads if necessary.

4. Verify loads are balanced within 10% line-to-line.

5. Check harness connections (P1 pin socket).

6. Measure field, quadrature, and main winding resistance. Clean slip rings and replace brushes if needed.

7. Check governor actuator and linkage for free, smooth motion.

Logic:

• Instantaneous Fault: Frequency is greater than 72 Hz.

• Delayed Fault: Frequency is greater than 66 Hz but less than 72 Hz for 6 continuous seconds.

Possible Causes:

• Generator set loads

• Engine governor function

• Fuel supply or air/fuel mixture issues

• Exhaust system blockage

Diagnosis and Repair:

1. Check the last fault recorded.

2. Measure AC current while running with loads to identify faulty or short cycling loads.

3. Check harness connection (P1 pin).

4. Check for a blocked or damaged exhaust system.

5. For propane models, check tank level and ensure correct propane grade for the ambient temperature.

6. Check fuel lines for damage.

Logic: Frequency is less than 54 Hz for 8 continuous seconds.

Possible Causes:

• Generator set loads

• Engine governor function

• Fuel supply or air/fuel mixture issues

• Exhaust system blockage

• Ignition or wiring problems

Diagnosis and Repair:

1. Verify the fuel shutoff valve is opening fully.

2. Measure AC current to identify faulty or short cycling loads.

3. Measure generator load capability with a load bank, derating for altitude/temperature if necessary.

4. Check harness connections (P1 and P2 pins).

5. Check for a damaged exhaust system.

6. Check fuel supply pressure.

7. Check the engine ignition system.

8. Measure winding resistances and inspect slip rings/brushes.

Logic: DC voltage to the controller is greater than 19 VDC.

Possible Causes:

• Wire damage

• Faulty battery charger (utility-powered or engine flywheel charger)

• Faulty control

Diagnosis and Repair:

1. Check the last fault recorded.

2. Measure DC voltage at the battery, generator set, and connector P1. Repair wiring if necessary.

3. Measure DC voltage with the battery charger turned on. If the voltage is near or above 19V, troubleshoot the appropriate battery charger (utility or flywheel).

4. Check harness connections (P1 pin socket).

Logic: The generator set control configuration does not meet any valid configuration, often after a control board replacement.

Possible Causes:

• Incorrect generator set configuration

• Faulty control

Diagnosis and Repair:

1. Check the last fault recorded.

2. Using the display, enter the “Generator Config” screen and correctly set the configuration options for your specific model and fuel type.

3. If the configuration is correct and the fault will not clear, replace the control board.

Logic: The total generator set load is above 105% of its rated capacity.

Possible Causes: Excessive load connected to the generator set.

Diagnosis and Repair:

1. Check the last fault recorded.

2. Measure the AC current and voltage while running the generator set with all connected loads.

a. Identify any faulty or short-cycling loads that may be causing spikes.

b. Reduce the connected loads as necessary. A load management kit can be used to automatically reduce loads.

Logic: The temperature at the alternator is too high. The high-temperature switch opens between 197 – 209 °F (91.5 – 98.5 °C), triggering the fault.

Possible Causes:

• Wire connections are faulty.

• The temperature switch is faulty.

• The generator set cooling fan or fan drive is faulty.

• Cooling air flow is inadequate (blocked vents).

Diagnosis and Repair:

1. Verify that the generator set air inlet and outlet panels are not obstructed and the enclosure is clear of foreign objects.

2. Check harness connections (P1 pin socket).

3. Measure the temperature sensor wiring for continuity to ground. If the circuit is open, check the harness and temperature switch for open conditions.

4. Visually inspect the cooling fan for missing or damaged blades and ensure it is securely connected to the rotor shaft.