®
Owner’s Manual and
Installation Instructions
CENTURION 3500
Air-cooled, Prepackaged
Automatic Standby Generator
• Model: 04791-0
3.4kW LP
Not intended for use as Primary Power in place of utility
or in life-support applications.
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This manual should
remain with the unit.
DEADLY EXHAUST FUMES. OUTDOOR INTALLATION ONLY!!
DANGER
Generac®Power Systems, Inc.
INTRODUCTION
Thank you for purchasing this model of the CENTURION product line by Generac Power Systems Inc.
This model is designed and manufactured to supply
electrical power for residences.
READ THIS MANUAL THOROUGHLY
If any portion of this manual is misunderstood, contact the nearest Generac Authorized Service Dealer
for starting, operating and servicing procedures.
Throughout this publication, and on tags and decals
affixed to the generator, DANGER, WARNING, CAUTION and NOTE blocks are used to alert personnel to
special instructions about a particular operation that
may be hazardous if performed incorrectly or carelessly. Observe them carefully. Their definitions are
as follows:
After this heading, read instructions that, if not
strictly complied with, will result in serious personal injury, including death, as well as property damage.
After this heading, read instructions that, if not
strictly complied with, may result in serious personal injury or property damage.
After this heading, read instructions that, if not
strictly complied with, could result in damage to
equipment and/or property.
NOTE:
After this heading, read explanatory statements
that require special emphasis.
These safety warnings cannot eliminate the hazards
that they indicate. Common sense and strict compliance with the special instructions while performing
the service are essential to preventing accidents.
Four commonly used safety symbols accompany the
DANGER, WARNING and CAUTION blocks. The type
of information each indicates follows:
This symbol points out important safety information that, if not followed, could endanger
personal safety and/or property of others.
This symbol points out potential explosion hazard.
This symbol points out potential fire hazard.
This symbol points out potential electrical
shock hazard.
CONTENTS
This manual contains pertinent owner’s information,
including warranty, electrical diagrams, exploded
views and lists of repair parts for generator model
numbers 04791-0. In addition, the latter portion of
this manual contains information necessary for the
proper installation of these generators.
OPERATION AND MAINTENANCE
It is the owner's responsibility to perform all safety
checks, to make sure that all maintenance for safe
operation is performed promptly, and to have the
equipment checked periodically by a Generac
Authorized Service Dealer. Normal maintenance service and replacement of parts are the responsibility of
the owner and, as such, are not considered defects in
materials or workmanship within the terms of the
warranty. Individual operating habits and usage contribute to the need for maintenance service.
Proper maintenance and care of the generator ensure
a minimum number of problems and keep operating
expenses at a minimum.
HOW TO OBTAIN SERVICE
When your generator requires servicing or repairs,
simply contact a Generac Authorized Service Dealer
for assistance. Service technicians are factory trained
and are capable of handling all service needs.
When contacting a Generac Authorized Service
Dealer about parts and service, always supply the
complete model number and serial number of the
unit as given on its data decal, which is located on the
generator.
Model No. ____________ Serial No. ______________
AUTHORIZED SERVICE
DEALER LOCATION
To locate the nearest GENERAC AUTHORIZED
SERVICE DEALER, please call this number:
1-800-333-1322
ONLY DEALER LOCATION INFORMATION
CAN BE OBTAINED AT THIS NUMBER.
DANGER
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Table of Contents
CENTURION 3500 Home Standby Generator
Generac®Power Systems, Inc. 1
Part I – Owner’s Manual
Introduction ........................................Inside Front Cover
Read This Manual Thoroughly ....................................IFC
Contents ......................................................................IFC
Operation and Maintenance ........................................IFC
How to Obtain Service..................................................IFC
Authorized Service Dealer Locator Number ................IFC
Safety Rules ........................................................................2
Section 1 - General Information ....................................4
1.1 Generator Identification ........................................4
1.2 Unpacking/Inspection ............................................5
1.3 Safety ....................................................................6
1.4 Protection Systems................................................6
1.5 Location ................................................................6
1.6 Specifications ........................................................6
Section 2 - Operation........................................................7
2.1 Generator Control Panel........................................7
2.2 Before Starting the Engine ....................................8
2.3 Battery Connection................................................8
2.4 The Battery ..........................................................9
2.5 Before Initial Start-up............................................9
2.6 Stopping the Generator ......................................10
2.7 Applying Loads to Generator ..............................10
2.8 Do Not Overload the Generator ..........................10
2.9 Protection Systems..............................................10
2.10 Additional Information ........................................12
Section 3 - Maintenance ................................................12
3.1 Checking the Engine Oil Level ............................12
3.2 Changing the Engine Oil and/or Oil Filter ..........12
3.3 Maintaining the Engine Air Cleaner ....................13
3.4 Clean Air Intake ..................................................14
3.5 Checking the Engine Spark Plug ........................14
3.6 Clean Spark Arrestor ..........................................14
3.7 Cleaning the Generator ......................................15
3.8 Battery Maintenance............................................15
3.9 Exercising the Generator ....................................16
3.10 Out of Service Procedure ....................................16
3.11 Adjusting Valve Clearance ..................................17
3.12 Generator Service Interval ..................................17
Part II – Installation Instructions
Safety Rules ......................................................................19
Section 1 - General Information ..................................21
1.1 Tools Required....................................................21
1.2 Items That Must Be Purchased ..........................21
1.3 Plan the Location of the Generator......................21
Section 2 - Installation ..................................................22
2.1 Site Preparation and Generator Placement ........22
2.2 Power Cord Installation ......................................22
2.3 Mount Power Transfer Motor ..............................23
2.4 Install Propane Tanks ........................................23
2.5 Set System for Automatic Operation ..................25
2.6 How to Keep the Regulator Operating
Efficiently & Safely ..............................................25
2.7 What is Regulator Freeze Up?..............................25
Appendix 1 - Troubleshooting ......................................26
Appendix 2 - Notes..........................................................27
Appendix 3 - Electrical Data ........................................30
Appendix 4 - Exploded Views and Parts Lists..........34
Appendix 5 - Warranty ..................................................48
2 Generac®Power Systems, Inc.
Study these SAFETY RULES carefully before
installing, operating or servicing this equipment.
Become familiar with this manual and with the unit.
The generator can operate safely, efficiently and reliably only if it is properly installed, operated and
maintained. Many accidents are caused by failing to
follow simple and fundamental rules or precautions.
Generac cannot possibly anticipate every possibility
that might involve a hazard. The warnings in this
manual, and on tags and decals affixed to the unit,
are, therefore, not all-inclusive. If using a procedure,
work method or operating technique Generac does
not specifically recommend, satisfy yourself that it is
safe for others. Also make sure the procedure, work
method or operating technique chosen does not render the generator unsafe.
Despite the safe design of this generator, operating this equipment imprudently, neglecting
its maintenance or being careless can cause
possible injury or death. Permit only responsible and capable persons to operate or maintain
this equipment.
Potentially lethal voltages are generated by
these machines. Ensure all steps are taken to
render the machine safe before attempting to
work on the generator.
Parts of the generator are rotating and/or hot
during operation. Exercise care near running
generators.
GEN
ERAL HAZARDS
• For safety reasons, Generac recommends that the
maintenance of this equipment is carried out by a
Generac Authorized Service Dealer.
• The generator engine releases DEADLY carbon
monoxide gas through its exhaust system. This
dangerous gas, if breathed in sufficient concentrations, can cause unconsciousness or even death.
Never operate the generator inside any garage or
other enclosed area. DO NOT OPERATE THE
GENERATOR IF THE EXHAUST SYSTEM IS
LEAKING OR HAS BEEN DAMAGED. SYMPTOMS
OF CARBON MONOXIDE POISONING ARE (a)
inability to think coherently, (b) nausea, (c) vomiting, (d) twitching muscles, (e) throbbing temples,
(f) dizziness, (g) headaches, (h) weakness, and (i)
sleepiness. IF EXPERIENCING ANY OF THESE
SYMPTOMS, MOVE INTO FRESH AIR IMMEDIATELY. IF SYMPTOMS PERSIST, GET MEDICAL
HELP. Shut down the generator and do not operate
it until it has been inspected and repaired.
• The engine exhaust fumes contain carbon monox-
ide, which can be DEADLY. This dangerous gas, if
breathed in sufficient concentrations, can cause
unconsciousness or even death. This exhaust system must be installed properly, in strict compliance with applicable codes and standards.
Following installation, do nothing that might render the system unsafe or in noncompliance with
such codes and standards. Never operate this
equipment with a leaking or defective exhaust system.
• Keep hands, feet, clothing, etc., away from drive
belts, fans, and other moving or hot parts. Never
remove any drive belt or fan guard while the unit is
operating.
• Adequate, unobstructed flow of cooling and venti-
lating air is critical to correct generator operation
and is required to expel toxic fumes and fuel vapors
from the generator. Without sufficient cooling airflow, the engine/generator overheats, which causes
serious damage to the generator. Do not alter the
installation or permit even partial blockage of ventilation provisions, as this can seriously affect safe
operation of the generator.
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Safety Rules
CENTURION 3500 Home Standby Generator
SAVE THESE INSTRUCTIONS – The manufacturer suggests that these rules for safe
operation be copied and posted in potential hazard areas of the recreational vehicle.
Safety should be stressed to all operators and potential operators of this equipment.
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!
The engine exhaust from this product
contains chemicals known to the state
of California to cause cancer, birth
defects or other reproductive harm.
WARNING:
This product contains or emits chemicals
known to the state of California to cause
cancer, birth defects or other reproductive harm.
WARNING:
SAVE THESE INSTRUCTIONS – This manual contains important instructions that should be
followed during installation and maintenance of the generator and batteries.
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DANGER
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Generac®Power Systems, Inc. 3
• When working on this equipment, remain alert at
all times. Never work on the equipment when
physically or mentally fatigued.
• Inspect the generator regularly, and contact the
nearest Generac Authorized Service Dealer immediately for parts needing repair or replacement.
• Before performing any maintenance on the generator, disconnect its battery cables to prevent accidental start up. Disconnect the cable from the battery post indicated by a NEGATIVE, NEG or (–)
first. Reconnect that cable last.
• Never use the generator or any of its parts as a
step. Stepping on the unit can stress and break
parts, and may result in dangerous operating conditions from leaking exhaust gases, fuel leakage,
oil leakage, etc.
ELECTRICAL HAZARDS
• The generator covered by this manual produces
dangerous electrical voltages and can cause fatal
electrical shock. Avoid contact with bare wires, terminals, connections, etc., while the unit is running.
Ensure all appropriate covers, guards and barriers
are in place before operating the generator. If work
must be done around an operating unit, stand on
an insulated, dry surface to reduce shock hazard.
• Do not handle any kind of electrical device while
standing in water, while barefoot, or while hands
or feet are wet. DANGEROUS ELECTRICAL
SHOCK MAY RESULT.
• During installation, have the generator properly
grounded (bonded) by means of an approved
bonding conductor. DO NOT disconnect the bonding conductor. DO NOT reconnect the bonding
conductor to any generator part that might be
removed or disassembled during routine maintenance. If the grounding conductor must be
replaced, use only a flexible conductor that is of
No. 12 American Wire Gauge (AWG) copper wire
minimum.
• In case of accident caused by electric shock, immediately shut down the source of electrical power. If
this is not possible, attempt to free the victim from
the live conductor. AVOID DIRECT CONTACT
WITH THE VICTIM. Use a nonconducting implement, such as a dry rope or board, to free the victim from the live conductor. If the victim is unconscious, apply first aid and get immediate medical
help.
• Never wear jewelry when working on this equipment. Jewelry can conduct electricity resulting in
electric shock, or may get caught in moving components causing injury.
FIRE HAZARDS
• For fire safety, the generator must be installed and
maintained properly. Installation always must
comply with applicable codes, standards, laws and
regulations. Adhere strictly to local, state and
national electrical and building codes. Comply
with regulations the Occupational Safety and
Health Administration (OSHA) has established.
Also, ensure that the generator is installed in
accordance with the manufacturer’s instructions
and recommendations. Following proper installation, do nothing that might alter a safe installation
and render the unit in noncompliance with the
aforementioned codes, standards, laws and regulations.
EXP
LOSION HAZ
ARDS
• Do not smoke around the generator. Wipe up any oil
spills immediately. Ensure that no combustible
materials are left in the generator compartment, or
on or near the generator, as FIRE or EXPLOSION
may result. Keep the area surrounding the generator clean and free from debris.
Safety Rules
CENTURION 3500 Home Standby Generator
4 Generac®Power Systems, Inc.
1. Generator Air Intake
2. Engine AUTO/OFF/MANUAL Switch
3. Fuse
4. LED Indicator
5. Demand Regulator (Inside Compartment)
6. Change-over Regulator
7. Circuit Breakers
8. Starter Contactor
9. Fuel Inlet
10. Tank Hook-ups.
11. Battery (In Compartment)
12. Oil Filter
13. Oil Drain (From Underside)
14. Oil Dipstick
15. Air Filter (Behind Access Panel)
16. Oil Fill
17. Spark Plug
18. Tank Hold Down Brace
19. Exhaust Hood
(Tailpipe and Spark Arrestor Inside)
20. Ground Lug
21. Data Decal (Located inside compartment)
Section 1 – General Information
CENTURION 3500 Home Standby Generator
Please record the following information from the generator DATA DECAL or information decal.
1. Model Number ____________________ 2. Serial Number __________________
3. kW Rating__________________________ 4. Rated Voltage __________________
072347
QT
RATO
R
T
OR
R
USE
.5A
1.1 GENERATOR IDENTIFICATION
Model: 004700-0 — QUIETPACT 40G
21
18
10
19
13
14, 16
12
8
17
4
3
7
2
15
1
9
6
5
1
11
20
GENERAT
F
POWE
7
PUSH TO RESE
R POWE
0.8L/0.84
Generac®Power Systems, Inc. 5
Section 1 – General Information
CENTURION 3500 Home Standby Generator
1.1.1 POWER TRANSFER MONITOR
The Power Transfer Monitor controls the automatic
function of the Centurion 3500 generator set. It’s six
foot utility sensing cord monitors the utility line when
it is plugged into a standard household 120 volt outlet.
NOTE:
Automatic start-up upon utility power outage will
not occur if six foot sensing cord is not plugged
into a utility powered 120 volt outlet.
Figure 1.2 — Power Transfer Monitor
1. Generator Power Conduit (15 foot)
2. Circuit Breaker Reset (2)
3. Generator Power Indicator Lamp
4. Utility Power Indicator Lamp
5. Generator Exercise Switch
6. Switched GFCI Outlet
7. Standby GFCI Outlet
8. Utility Sensing Cord (6 foot)
1.1.1.1 Generator Power Conduit
This conduit connects the Power Transfer Monitor,
which is located inside the home, to the generator
outside.
1.1.1.2 Circuit Breaker Reset
If the generator should experience an overload for
any reason, the circuit breaker(s) will trip. The circuit breaker reset(s) should be pushed to reset after
overload condition has been corrected.
1.1.1.3 Generator Power Indicator Lamp
This lamp will illuminate when the generator has
started and is supplying power to the Power Transfer
Monitor’s GFCI outlets.
1.1.1.4 Utility Power Indicator Lamp
This lamp will be illuminated when normal utility
power is available.
1.1.1.5 Generator Exercise Switch
This switch activates the exercise cycle of the generator. Make sure the combined loads do not exceed generator capacity.
1.1.1.6 Switched GFCI Outlet
This outlet is powered by the utility and by the generator. When utility power is present is acts as another normal household outlet. When the generator is
supplying power this outlet is then being supplied
with power from the generator.
NOTE:
There will be a momentary “No Power” period
between the time of utility failure and the generator start up.
1.1.1.7 Standby GFCI Outlet
This outlet is ONLY powered by the generator. Use it
for additional items during a utility power outage
when the generator is providing backup electricity for
the home.
1.1.1.8 Utility Sensing Cord
When plugged into a standard grounded 120 volt outlet this cord allows the Power Transfer Monitor to
sense the utility line condition and react to a power
outage.
1.2 UNPACKING/INSPECTION
After unpacking, carefully inspect the contents for
damage.
• This standby generator set has been factory supplied with a weather protective enclosure that is
intended for outdoor installation only.
• This standby generator set is prepackaged with an
automatic power transfer monitor. The power
transfer monitor is prewired with 15 foot conduit
and six foot utility sensing cord with plug. The
Power Transfer Monitor is for indoor installation
only.
If any loss or damage is noted at time of delivery, have
the person(s) making the delivery note all damage on
the freight bill or affix his or her signature under the
consignor’s memo of loss or damage.
If loss or damage is found after delivery, separate the
damaged materials and contact the carrier for claim
procedures if applicable.
Use this generator to supply electrical power for
operating 120-volt, single-phase, 60 Hertz, AC electrical loads. These loads can require up to 3,400
watts (3.4 kW) of power, but cannot exceed 28.3 AC
amperes of current at 120 volts.
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1
2
3
4
5
6
7
8
6 Generac®Power Systems, Inc.
Section 1 – General Information
CENTURION 3500 Home Standby Generator
Do not overload the generator. Some installations may require that electrical loads be alternated to avoid overloading. Applying excessively high electrical loads may damage the
generator and may shorten its life. Add up the
rated watts of all electrical lighting, appliance,
tool and motor loads the generator will power
at one time. This total should not be greater
than the wattage capacity of the generator. If
an electrical device nameplate gives only volts
and amps, multiply volts times amps to obtain
watts (volts x amps = watts). Some electric
motors require more watts of power (or amps
of current) for starting than for continuous
operation.
1.3 SAFETY
Before attempting to use the generator set, carefully
read the “Safety Rules” section of this manual.
Comply strictly with these rules to prevent accidents
and damage to equipment and/or property. We suggest copying and posting the “Safety Rules” in potential hazard near the generator. Stress safety to all
operators and potential operators of this equipment.
1.4 PROTECTION SYSTEMS
Unlike an automobile engine, the generator may have
to run for long periods of time with no operator present to monitor engine conditions. For that reason,
the engine is equipped with the following systems
that protect it against potentially damaging conditions:
1. Overcrank
2. Overspeed
3. Low Oil Pressure Sensor
4. High Temperature Sensor
5. Underspeed
There is an LED readout on the control panel to noti-
fy personnel that one of these faults has occurred.
Detail of of the protection systems can be found in
Section 2.9.
1.5 LOCATION
Install the generator set, in its protective enclosure,
outdoors, where adequate cooling and ventilating air
is always available. Consider these factors:
• Install the unit where air inlet and outlet openings
will not become obstructed by leaves, grass, snow,
etc. If prevailing winds will cause blowing or drifting, consider using a windbreak to protect the unit.
• Install the generator on high ground where water
levels will not rise and endanger it.
• Allow sufficient room on all sides of the generator
for maintenance and servicing. A good rule is to
allow three feet of space on all sides.
• Where strong prevailing winds blow from one
direction, face the generator air inlet openings to
the prevailing winds.
1.6 SPECIFICATIONS
1.6.1 FUEL REQUIREMENTS AND RECOMMENDATIONS
With LP gas, use only the LP vapor withdrawal system. This type of system uses the vapors formed
above the liquid fuel in the storage tank.
Recommended fuel should have a BTU content of at
least 2,520 BTU's per cubic foot. Ask the LP fuel supplier for the BTU content of the fuel.
This generator has been designed for a specific type
of tank. Acceptable tank types are DOT-4BA240 and
DOT-4BW240. Any deviation in tank type may not
allow the tank to fit in the LP enclosure.
Gaseous fuels such as liquid propane (LP) gas
are highly explosive. Even the slightest spark
can ignite such fuels and cause an explosion.
No leakage of fuel is permitted. LP gas, which
is heavier than air tends to settle in low areas.
1.6.2 FUEL CONSUMPTION
Fuel consumption is in gal/hr.
1.6.3 ENGINE OIL REQUIREMENTS
Use only high quality detergent oil rated with
American Petroleum Institute (API) Service
Classification SF, SG or SH. The recommended oil
weights include the following:
• During summer months: SAE 30. An acceptable
substitute is SAE 10W-30.
• During winter months: SAE 5W-30. DO NOT USE
SAE 10-W40.
Crankcase and oil filter capacity is approximately
800 mL or .84 U.S. quarts. Do NOT use special additives. See Sections 3.1 and 3.2 for oil level check and
fill procedures.
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Model 1/2 Load Full Load
Centurion 3500 0.55 0.73
(04791-0)
DANGER
Generac®Power Systems, Inc. 7
Section 2 – Operation
CENTURION 3500 Home Standby Generator
1.6.4 ENGINE
Type of Engine ............................GN-220, Single-cylinder
Cooling Method..................................................Air-cooled
Rated Horsepower ..................................7.8 @ 4,200 rpm
Displacement............................................................220cc
Cylinder Block ....................Aluminum w/Cast Iron Sleeve
Type of Governor ........................Mechanical, Fixed Speed
Air Cleaner ..................Paper Element w/Foam Precleaner
Starter ................................................12-volt DC Electric
Ignition System ................Solid-state w/Flywheel Magneto
Recommended Spark Plug
Champion ..........................................................RC12YC
AC ..........................................................................R45S
Fram Autolite ..............................................................65
Spark Plug Gap ..................................0.03. inch (76 mm)
Recommended Minimum
Battery ......................................235cc Amperes @ 32°F/
195cc Amperes @ 0° F
1.6.5 GENERATOR
Rated Maximum Continuous
AC Output (LP)................................3,400 Watts (3.4kW)
Rated Voltage ................................................120 Volts AC
Rated Maximum Continuous
AC Current (LP) ........................................28.3 Amperes
Phase ......................................................................Single
Rotor RPM................................................................3,600
Number of Rotor Poles ....................................................2
Engine RPM..............................................................3,600
Rated AC Frequency ................................................60 Hz
Battery Charge Voltage ....................................14 Volts DC
Battery Charge Current ..........................2 Amperes (max)
Length ..................................................843 mm (33.2 in.)
Width ....................................................504 mm (19.8 in.)
Height ......................................................966 mm (38 in.)
Weight ......................................................90 kg (275 lbs.)
2.1 GENERATOR CONTROL PANEL
The following features are mounted on the generator
control panel (Figure 2.1):
Figure 2.1 — Generator Control Panel
2.1.1 SHUT DOWN INDICATOR
This LED will flash a specific number of times to indicate a specific failure. Shutdowns and their failure
codes follow in Section 2.9, Protection Systems. These
codes can also be referenced on the decal located on
the air filter cover, located below the control panel.
2.1.2 AUTO/OFF/MANUAL SWITCH
2.1.2.1 Auto Position
Selecting this switch position activates fully automatic system operation. It also allows the user the ability to start and exercise the generator from the remote
Power Transfer Monitor.
2.1.2.2 Off Position
This switch position shuts down the engine. This
position also prevents the engine from starting.
2.1.2.3 Manual Position
Selecting this switch position will crank and start the
engine. Transfer to standby power will not occur
unless there is a utility failure.
With the switch set to AUTO, the engine may
crank and start at any time without warning.
Such automatic starting normally occurs when
utility power source voltage drops below a preset level or during the normal exercise cycle. To
prevent possible injury that might be caused by
such sudden starts, always set the switch to
OFF and remove the fuse before working on or
around the generator or transfer switch. Then,
place a “Do Not Operate” tag on the generator
panel and on the transfer switch.
2.1.3 FUSE
The generator panel's 7.5 amp fuse protects the DC
control circuit against overload. The fuse is wired in
series with the battery output lead to the panel. If the
fuse element has melted open, the engine cannot
crank or start. The same fuse also protects the battery charge circuit against overload. If the fuse element has melted open, battery charging will not be
possible. Replace the fuse using only an identical 7.5
amp fuse.
2.1.4 MAIN BREAKERS
The main breakers protect the generator’s AC output
circuit against overload and provide a method of
turning OFF the generator’s 120-volt AC output to the
Power Transfer Monitor’s outlets. The CENTURION
3500 has two (2) 15-amp breakers.
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✧ ✧ ✧
FUSE
7.5A
SHUT
DOWN
GENERATOR
POWER
GREEN BAR INDICATES TRIP
PUSH TO RESET
15 15
PULL TO DISCONNECT
GENERATOR POWER
INDICATOR
SEE CHART
BELOW FOR
DETAILS
CONTROL CENTER
AUTO
OFF
MAN.
8 Generac®Power Systems, Inc.
Section 2 – Operation
CENTURION 3500 Home Standby Generator
2.2 BEFORE STARTING THE ENGINE
NOTE:
Instructions and information in this manual
assume the generator has been properly installed
and connected.
2.2.1 ENGINE LUBRICATION
Have the engine crankcase properly serviced with the
recommended oil before starting. Refer to Section
1.6.2 and Sections 3.1 and 3.2, for oil servicing procedures and recommendations.
Any attempt to crank or start the engine before
it has been properly serviced with the recommended oil may result in an engine failure.
2.2.2 FUEL SUPPLY
The engine must have an adequate supply of proper
fuel to operate. Before starting it, check that sufficient
fuel is available.
2.2.3 COOLING AND VENTILATING AIR
Air inlet and outlet openings in the generator compartment must be open and unobstructed for continued proper operation. Without sufficient cooling and
ventilating airflow, the engine/generator overheats,
which causes it to shut down and may damage the
generator.
2.2.4 ENGINE EXHAUST GAS
Before starting the generator engine, be sure there is
no way for exhaust gases to endanger people or animals. Close windows, doors near the generator that,
if open, might permit exhaust gases to do so.
The generator engine releases DEADLY carbon
monoxide gas through its exhaust system. This
dangerous gas, if breathed in sufficient concentrations, can cause unconsciousness or even
death. Never operate the generator set inside
any enclosed area. make sure THE EXHAUST
SYSTEM IS not LEAKING AND HAS NOT BEEN
DAMAGED. SYMPTOMS OF CARBON MONOXIDE POISONING ARE (a) inability to think coherently, (b) nausea, (c) vomiting, (d) twitching
muscles, (e) throbbing temples, (f) dizziness, (g)
headaches, (h) weakness, and (i) sleepiness. IF
EXPERIENCING ANY OF THESE SYMPTOMS,
MOVE INTO FRESH AIR IMMEDIATELY. IF SYMPTOMS PERSIST, GET MEDICAL HELP. Shut down
the generator and do not operate it until it has
been inspected and repaired.
2.3 BATTERY CONNECTION
Before connecting the battery, complete the following
steps:
1. Set the generator's AUTO/OFF/MANUAL switch to
OFF.
2. Make sure the Power Transfer Monitor’s sensing
cord (6 foot) is not plugged into an electrical outlet.
If the AUTO/OFF/MANUAL switch is not set to
its OFF position, the generator can crank and
start as soon as the battery cables are connected. If the utility power supply is not disabled
by unplugging the 6 foot sensing cord from
electrical outlet, sparking can occur at the battery posts and cause an explosion.
Battery cables were factory connected at the generator (Figure 2.2). Connect the cables to the battery
posts using the hardware supplied in the manual bag
as follows:
3. Slide the red battery terminal boot over the battery cable, then connect the cable (from the
starter contactor) to the battery post indicated by
a positive, POS or (+).
4. Connect the black battery cable (from frame
ground) and the two green grounding wires (from
the control panel) to the battery post indicated by
a negative, NEG or (-).
NOTE:
Damage will result if battery connections are made
in reverse.
Figure 2.2 — Battery Cable Connections
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DANGER
DANGER
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Generac®Power Systems, Inc. 9
Section 2 – Operation
CENTURION 3500 Home Standby Generator
2.4 THE BATTERY
Servicing of the battery is to be performed or supervised by personnel knowledgeable of batteries and
the required precautions. Keep unauthorized personnel away from batteries.
When replacing the battery, use the following type of
battery, Group U1 12-volt battery with a rating of 235
cold-cranking amps at 0° C (32° F); 195 cold-cranking amps at -17.8º C (0º F) minimum. When using a
maintenance-free battery, it is not necessary to check
the specific gravity or electrolyte level. Have these
procedures performed at the intervals specified in
the “Service Schedule.” A negative ground system is
used. Battery connections are shown on the wiring
diagrams. Make sure the battery is correctly connected and terminals are tight. Observe battery polarity
when connecting the battery to the generator set.
Do not dispose of the battery in a fire. The battery is capable of exploding.
A battery presents a risk of electrical shock and
high short circuit current. The following precautions are to be observed when working on batteries:
• Remove watches, rings or other metal objects;
• Use tools with insulated handles;
• Wear rubber gloves and boots;
• Do not lay tools or metal parts on top of the battery; and
• Disconnect charging source prior to connecting or
disconnecting battery terminals.
Do not open or mutilate the battery. Released
electrolyte has been known to be harmful to
the skin and eyes, and to be toxic.
The electrolyte is a dilute sulfuric acid that is
harmful to the skin and eyes. It is electrically
conductive and corrosive. The following procedures are to be observed:
• Wear full eye protection and protective clothing;
• Where electrolyte contacts the skin, wash it off
immediately with water;
• Where electrolyte contacts the eyes, flush thoroughly and immediately with water and seek medical attention; and
• Spilled electrolyte is to be washed down with an
acid neutralizing agent. A common practice is to
use a solution of one pound (500 grams) bicarbonate of soda to one gallon (4 liters) or water. The
bicarbonate of soda solution is to be added until
the evidence of reaction (foaming) as ceased. The
resulting liquid is to be flushed with water and
the area dried.
Lead-acid batteries present a risk of fire
because they generate hydrogen gas. The following procedures are to be followed:
• DO NOT SMOKE when near the battery;
• DO NOT cause flame or spark in battery area; and
• Discharge static electricity from body before touching the battery by first touching a grounded metal
surface.
Be sure the AUTO/OFF/MANUAL switch is set to
the OFF position before connecting the battery
cables. If the switch is set to AUTO or MANUAL,
the generator can crank and start as soon as
the battery cables are connected.
2.5 BEFORE INITIAL START-UP
Before starting the generator, complete the following:
1. Set the generator's main circuit breakers (located
in generator’s control panel) to their OFF or
OPEN positions by pulling the reset buttons outward. A visible GREEN stripe should appear.
2. Set the generator's AUTO/OFF/MANUAL Switch to
the OFF position.
3. Turn OFF all loads connected to the Power
Transfer Monitor through the GFCI outlets.
4. Check the engine crankcase oil level and, if nec-
essary, fill to the dipstick full mark with the recommended oil. Do not fill above the oil FULL
mark.
5. Check the fuel supply. Both tanks should be full.
6. The changeover valve tank indicator should be
GREEN.
2.5.1 INITIAL START UP - PURGING THE
FUEL SYSTEM
To purge the air that is in the lines of the fuel
system, perform the following:
1. Connect the LP tanks and open both tank valves.
Make sure that the selector lever on the
changeover regulator is pointing at one of the two
tanks. Also verify that the Full/Empty indicator on
top of the changeover regulator is GREEN.
2. Set the generator's main circuit breakers to their
OFF or OPEN positions by pulling the reset buttons outward. A visible Green stripe should
appear.
3. Move the AUTO/OFF/MANUAL switch to the MANUAL position.
!
DANGER
!
!
10 Generac®Power Systems, Inc.
Section 2 – Operation
CENTURION 3500 Home Standby Generator
4. The engine will crank and attempt to start for
approximately 15 seconds. Due to the air that will
be in the fuel lines, the engine may not start during the first 15 second cranking cycle. If the
engine does not start during the first crank cycle,
it will rest for approximately 15 seconds and then
attempt to start again. The complete starting
cycle is as follows:
• 15 seconds ON
• 15 seconds OFF
• 7 seconds ON
• 7 seconds OFF
• Repeat for 45 seconds, Approximately 90 seconds total. The engine should start during the
first or second attempt.
5. If the unit does not start during this crank cycle,
verify that all fuel connections are tight and that
the tank valves are open. Turn the
AUTO/OFF/MANUAL switch to the OFF position,
wait 3-5 seconds, then repeat steps 3-4.
6. If the engine does not start after repeating steps
3-4, contact the nearest Generac Authorized
Service Dealer for assistance.
2.5.2 CHECKING AUTOMATIC OPERATION
To check the system for proper automatic operation,
proceed as follows:
1. Set the generator's main circuit breakers to their
OFF or OPEN positions by pulling the reset buttons outward. A visible GREEN stripe should
appear.
2. Check that the AUTO/OFF/MANUAL switch is set
to OFF.
3. Turn ON the utility power supply to the Power
Transfer Monitor by plugging the 6-foot sensing
cord into a standard household outlet.
4. Set the generator's main circuit breakers to their
ON or CLOSED position by pressing in the reset
buttons.
5. Set the AUTO/OFF/MANUAL switch to AUTO, the
system is now ready for automatic operation.
6. Turn off the utility power supply to the Power
Transfer Monitor by unplugging it’s 6-foot power
cord from the household outlet.
Once the Power Transfer Monitor senses the utility
source power is turned OFF, and after an approximate five second delay, the engine should crank and
start. After starting, the Power Transfer Monitor
should connect load circuits to the standby or generator side. Both sets of GFCI outlets on the Power
Transfer Monitor should have power. Confirm transfer of power by depressing the test buttons on both
GFCI outlets. Each one should trip and the indicator
will illuminate.
With the generator running and power is available to
the GFCI outlets, turn the utility power supply ON
once again by plugging the six foot power cord into a
standard household outlet. The following should
occur.
• The Power Transfer Monitor should sense the
return of utility power and transfer the loads
plugged into the SWITCHED GFCI back to the utility source. Any loads connected to the STANDBY
GFCI will remain powered by the generator until it
shuts down. In the event of a real outage, these
loads would be reconnected to the utility.
• About two minutes after re-transfer, the engine
should shut down. However, if the engine was not
run for it's minimum run time based on starting
time, it may run for a longer period of time before
shutting down. (20 minutes max.)
• The minimum run time is pre-programmed into
the generator micro processor and is provided to
ensure that the starting battery is fully charged
before the engine shuts down. The minimum run
time is based on the time it takes for the engine to
crank and start. For every one second of cranking,
the generator will run for 1.5 minutes.
2.6 STOPPING THE GENERATOR
1. Turn OFF all electrical loads using the means
provided (such as the generator fs main circuit
breakers).
2. Let generator run at no-load for a few minutes, to
stabilize internal engine generator temperatures.
3. Place the AUTO/OFF/MANUAL switch in its OFF
position.
2.7 APPLYING LOADS TO GENERATOR
When applying electrical loads to the generator,
observe these guidelines:
Before applying electrical loads, let the generator
stabilize and warm up for a minute or two.
DO NOT overload the generator.
2.8 DO NOT OVERLOAD THE
GENERATOR
Read the rated wattage/amperage capacity of the generator in GENERATOR data, (see Section 1.6.5).
Applying electrical loads in excess of the unit’s rated
capacity will cause the engine/generator to automatically shut down.
To avoid overloading, add up the wattage of all connected electrical lighting, appliance, tool and motor
loads. This total should not be greater than the generator’s rated wattage capacity.
Generac®Power Systems, Inc. 11
Section 3 – Maintenance
CENTURION 3500 Home Standby Generator
• Most lighting, appliance, tool and motor loads indicate their required watts on their nameplate or
data plate. For light bulbs, simply note the wattage
rating of the bulb.
• If a load does not show its rated wattage, multiply
that load’s rated VOLTS times AMPS to obtain
WATTS.
• Induction type motors (such as those that run a
furnace fan, refrigerator, window air conditioner,
etc.) need about 2-1/2 time more watts of power for
starting than for running (for a few seconds during
motor starting). Be sure to allow for this when connecting electrical loads to the generator. First, figure the watts needed to start electric motors in the
system. To that figure, add the running wattages of
other items that will be operated by the generator.
• Do not apply heavy electrical loads for the first two
or three hours of operation.
2.9 PROTECTION SYSTEMS
2.9.1 OVERCRANK — 2 FLASHES OF LED
This feature prevents the generator from damaging
itself when it continually attempts to start and another problem, such as no fuel supply, prevents it from
starting. The unit will crank and rest for a preset time
limit. Then, it will stop cranking, and the LED will
light indicating an overcrank failure. The AUTO/OFF/
MANUAL switch will need to be set to OFF and then
back to AUTO to reset the generator control board.
NOTE:
If the fault is not repaired, the overcrank feature
will continue to activate.
2.9.1.1 Approximate Crank Cycle Times
• 15 seconds ON
• 15 seconds OFF
• 7 seconds ON
• 7 seconds OFF
• Repeat for 45 seconds
Approximately 90 seconds total
2.9.2 OVERSPEED — 3 FLASHES OF LED
This feature protects the generator from damage by
shutting it down if it happens to run faster than the
preset limit. This protection also prevents the generator from supplying an output that could potentially
damage appliances connected to the generator circuit. Please reference Appendix 1, Troubleshooting, if
this fault occurs.
2.3.3 LOW OIL PRESSURE SWITCH —
4 FLASHES OF LED
This switch (Figure 2.2) has normally closed (N.C.)
contacts that are held open by engine oil pressure
during cranking and operating. Should oil pressure
drop below a preset level, switch contacts close, and
the engine automatically shuts down. The unit should
not be restarted until oil is added. Please reference
Appendix 1, Troubleshooting, if this fault occurs.
2.9.4 HIGH TEMPERATURE SWITCH —
5 FLASHES OF LED
This switch (Figure 2.2), which has normally open
(N.O.) contacts, is mounted near the oil filter. The
contacts close if the temperature should exceed
approximately 284° F (140° C), initiating an engine
shutdown. Please reference Appendix 1,
Troubleshooting, if this fault occurs.
Figure 2.3 — Low Oil Pressure and High
Temperature Switches
2.9.5 UNDERSPEED — 6 FLASHES OF LED
This feature protects the generator from damage by
shutting down if it happens to run slower than the
preset limit. Please reference Appendix 1,
Troubleshooting, if this fault occurs.
2.9.6 FIELD BOOST
The Controller Circuit Board houses a field boost
diode and resistor. These two components are part of
a “field boost” circuit (Figure 2.4). During engine
cranking only, a positive DC (battery) voltage is delivered through the diode, resistor, brushes and slip
rings, to the generator rotor. Application of this voltage to the rotor “flashes the field” whenever it is started. Flashing of the field each time the generator starts
makes sure that a sufficiently strong magnetic field is
available to produce “pickup” voltage in the stator
windings.
✧
High Temperature Switch
Low Oil Pressure
Switch
12 Generac®Power Systems, Inc.
Section 3 – Maintenance
CENTURION 3500 Home Standby Generator
Figure 2.4 — Field Boost Circuit
2.9.7 OVERVOLTAGE PROTECTION
A solid-state voltage regulator (Figure 2.5) controls
the generator’s AC output voltage. This regulator supplies an excitation current to the rotor. By regulating
the rotor’s excitation current, the strength of its magnetic field is regulated and, in turn, the voltage delivered to connected electrical loads is controlled. When
the AC frequency is 60 Hertz, voltage is regulated at
120 volts (voltage-to-frequency ratio is 2-to-1).
Figure 2.5 — Solid State Voltage Regulator
The voltage regulator also incorporates a “voltage
surge protection circuit”. This circuit prevents troublesome surges in the generator AC output voltage.
Voltage surge is a common cause of damage to electronic equipment.
2.10 ADDITIONAL INFORMATION
2.10.1 BREAK-IN PERIOD
The first few hours of operation is the break-in period for the generator. Properly breaking in the generator is essential to minimize fuel consumption and
provide maximum engine performance. During this
break-in period, follow this procedure:
• Run the unit at different electrical loads by plugging items into the Power Transfer Monitor’s outlets. This will help seat the engine piston rings
properly.
• Check the engine oil level frequently. Add oil if
needed. It is normal for the generator engine to
consume more oil than is normal until the piston
rings have properly seated.
• After operating the unit for the break-in period,
complete the tasks recommended under Section
2.10.2.
2.10.2 POST BREAK-IN CHECK-UP
After the break-in period, the owner should perform
the following maintenance items:
• Change the engine crankcase oil and oil filter.
• Check the oil level.
• Inspect the cooling and ventilation openings.
• Check the engine ignition system.
• Inspect the entire electrical system.
• Inspect the engine exhaust system.
2.10.3 ATTENTION REQUIRED AFTER
SUBMERSION
If the generator has been submerged in water, it
MUST NOT be started and operated. Following any
submersion in water, have a Generac/Centurion
Authorized Service Dealer thoroughly clean and dry
the generator.
2.10.4 OPERATION IN HIGH GRASS OR
BRUSH
Never operate the generator while it is in contact with
high grass, weeds, brush, leaves or any other combustible substance. Such materials can ignite and
burn from the heat of the exhaust system. The generator exhaust system becomes extremely hot during
operation and remains hot for a long time after it has
shut down.
2.10.5 EFFECTS OF MOISTURE AND DIRT
Keep the generator set as clean and dry as possible.
Protect the unit against excessive dust, dirt, corrosive
vapors, etc. Permitting dirt and moisture to accumulate on generator windings will have an adverse effect
on the insulation resistance of those windings.
When moisture is allowed to remain in contact with
windings, some of the moisture will be retained in
voids and cracks in the insulation. This causes a
reduced insulation resistance and will eventually
cause problems. Dirt will make the problem worse,
since dirt tends to hold moisture in contact with
windings. Salt (as from sea air) also will worsen the
problem since it tends to absorb moisture from the
air. Salt and moisture, when combined, form an electrical conductor which is detrimental to the generator.
CONTROLLER
CIRCUIT
BOARD
4
O
GRND
F
CLOSEST TO
BEARING
FIELD
Section 3 – Maintenance
CENTURION 3500 Home Standby Generator
3.1 CHECKING THE ENGINE OIL
LEVEL
For oil capacities and requirements, see “Engine Oil
Requirements,” Section 1.6.3. Check the engine
crankcase oil level weekly. To check the engine oil
level, proceed as follows (see Figure 3.1):
1. Remove the oil fill/dipstick cap and wipe the dip-
stick dry with a clean, lint-free cloth.
2. Install and tighten the oil fill/dipstick cap; then,
remove it again. The oil level should be at the dipstick “Full” mark.
3. If necessary, slowly add oil until it reaches the
dipstick “FULL” mark. DO NOT FILL ABOVE
THE “FULL” MARK.
Never operate the engine with the oil level
below the “Add” mark on the dipstick. Doing
this could damage the engine.
4. Install and tighten the oil fill/dipstick cap before
operating the engine.
3.2 CHANGING THE ENGINE OIL
AND/OR OIL FILTER
• Change the engine oil after the break-in period,
(see Section 2.10.1). Thereafter, change oil every
twelve months. Change the oil more frequently if
unit operates during extended power outages of
several days at a time, in dusty conditions or at
high ambient temperatures.
• Change the engine oil filter after the break-in peri-
od, and every twelve months thereafter.
To change the oil and/or oil filter, proceed as follows
(see Figure 3.1):
1. Run the engine until it is thoroughly warmed up
(at least five minutes) then shut OFF the engine.
2. Immediately after the engine shuts OFF, remove
the plug from the tube with a 5/16” allen wrench
and drain the oil into a suitable container.
Loosening the oil fill/dipstick cap will allow the
crankcase to drain faster.
3. After the oil has drained, replace the plug onto
the end of the oil drain tube.
4. With the oil drained, remove the old oil filter by
turning it counterclockwise. Place a towel underneath to catch excess oil.
5. Apply a light coating of clean engine oil to the gasket of the new filter. Fill the filter until saturated
with clean oil.
6. Screw the new filter on by hand until its gasket
lightly contacts the oil filter adapter. Then, tighten the filter an additional 3/4 to one turn.
7. Remove the oil fill/dipstick cap and wipe the dipstick dry with a clean, lint-free cloth. This will be
used later to check the oil level.
8. Slowly add the proper type and amount of recommended oil (see Section 1.6.3). Periodically
use the dipstick to check the oil level and continue to fill the crankcase until the oil reaches the
dipstick “Full” mark. DO NOT FILL ABOVE THE
“FULL” MARK.
9. Install and tighten the oil fill/dipstick cap before
operating the engine.
10. Start the engine and check for leaks.
NOTE:
Check the oil level and fill to the “FULL” mark
after checking for leaks. The filter will retain some
oil.
!
Generac®Power Systems, Inc. 13
Figure 3.1 – Oil Maintenance Features
Dipstick & Oil Fill
Oil Drain
(Underneath)
Oil Filter
GENERATOR
FUSE
POWER
7.5A
GREEN BAR INDICATES TRIP
PUSH TO RESET
PULL TO DISCONNECT
GENERATOR POWER
SHUT
DOWN
INDICATOR
SEE CHART
BELOW FOR
MAN.
AUTO
OFF
DETAILS
CONTROL CENTER
SERVICEACCESS PANEL
GENERATOR SHUTDOWN
S
O
E
N
O
L
INFORMATION SYSTEM
FAULTSIGNAL
2 FLASHES =
OVERCRANK
3 FLASHES =
OVERSPEED
LOW OIL PRESSURE
4 FLASHES =
5 FLASHES =
HIGH OIL TEMP
6 FLASHES = UNDERSPEED
MAINTENANCE SCHEDULE
OIL LEVEL:
AIR FILTER:
LOCATED BEHIND PANEL
*
OIL & OIL FILTER:
SPARK PLUGS:
REPLACEMENT INFORMATION
PREFILTER P/N:
AIR FILTER P/N:
OIL FILTER P/N:
SPARK PLUG P/N:
OIL CAPACITY WITH FILTER:
TEMPERATURE
40˚F AND HIGHER
-20˚F TO 40˚F
API SERVICE CLASSIFICATION SF, SG OR SH
WHEN SERVICE OR PARTS ARE NEEDED IN
THE USA OR CANADA, CONTACT THE GENERAC
SERVICE LOCATOR AT 1-800-333-1322.
CHECK DAILY
CLEAN PREFILTER
EVERY 100 HOURS.
REPLACE ELEMENT
EVERY 250 HOURS.
CHANGE EVERY 100
HOURS. (OR ANNUALLY)
PERFORM MORE OFTEN IN DUSTY CONDITIONS
*
INSPECT & CLEAN
PLUGS EVERY 500
HOURS. REPLACE PLUGS
IF NECESSARY
SAE VISCOSITY
SAE 30 OR 10W-30
5W-30 OR 5W-20
SEE OWNERS
MANUAL
FOR FURTHER
EXPLANATION
}
*
*
*
0D4511
0D9723
070185
072347
0.8L/0.84QT
14 Generac®Power Systems, Inc.
3.3 MAINTAINING THE ENGINE AIR
CLEANER
3.3.1 CLEANING THE FOAM PRECLEANER
Clean and re-oil the foam precleaner every six
months. Service the foam precleaner more frequently if operating the generator in extremely dusty or
dirty conditions. Use the following procedure (Figure
3.2):
Figure 3.2 — Engine Air Cleaner
1. Turn the two screws counterclockwise to loosen.
2. Remove the cover, foam precleaner and paper fil-
ter.
3. Remove the foam precleaner from the cover.
4. Wash the foam precleaner in liquid detergent and
water.
5. Wrap the foam precleaner in a clean cloth and
gently squeeze it dry.
6. Saturate the foam precleaner in clean engine oil.
Gently squeeze it in a clean cloth to remove
excess oil and to distribute oil (DO NOT TWIST).
7. Install the foam precleaner into the cover, fol-
lowed by the paper filter.
8. Install the cover, foam precleaner and paper filter.
9. Tighten the two screws to retain the filter in place.
3.3.2 CLEANING OR REPLACING THE PAPER
FILTER
Once each year or more frequently if operating in
dirty or dusty conditions, clean or replace the paper
filter. The new replacement filter must be flame retardant. Service the paper filter more frequently if operating the generator in extremely dusty or dirty conditions. Use the following procedure (Figure 3.2):
1. Follow steps 1-3 in Section 3.3.1; service the
foam precleaner if necessary.
2. Remove the paper filter.
3. Clean the air filter by tapping it gently on a solid
surface. If the filter is too dirty, replace it with a
new one. Dispose of the old filter properly.
4. Clean the air cleaner cover then reassemble following steps 7-9 in Section 3.3.1.
3.4 CLEAN AIR INTAKE
Clean all foreign material from the air intake (Figure
3.3) at least once every six months. Clean more often
if necessary.
Inspect the area around the generator periodically
and remove all grass, leaves, etc., from area.
Figure 3.3 — Cleaning Air Intake
3.5 CHECKING THE ENGINE SPARK
PLUG
Clean the spark plug and reset the spark plug gap
annually. Replace spark plug when the electrodes
have worn to the point where the proper gap cannot
accurately be set, or if the insulation is cracked.
1. Clean the area around the base of the spark plug
to keep dirt and debris out of the engine. Remove
the spark plug and check the condition. Replace
the spark plug if worn or if reuse is questionable.
2. Clean spark plug by scraping or washing using a
wire brush and commercial solvent. Do not blast
the spark plug to clean.
3. Check the spark plug gap using a wire feeler
gauge. Adjust the gap to 0.030 inch (0.76 mm) by
carefully bending the ground electrode (Figure
3.4).
Figure 3.4 — Setting the Spark Plug Gap
USTC
Section 3 – Maintenance
CENTURION 3500 Home Standby Generator
USTC
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