Generac 004721-0, 004722-0, 004723-0, 004724-0, 004725-0 User Manual

Owner’s Manual

ONLY QUALIFIED ELECTRICIANS OR CONTRACTORS SHOULD ATTEMPT

INSTALLATION!!

DEADLY EXHAUST FUMES. OUTDOOR INSTALLATION ONLY!

This manual should remain with the unit.

Not intended for use in critical life support applications.

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Liquid-cooled, Prepackaged

Standby Generators

Model Numbers

004721-0, 004722-0,
004723-0, 004724-0,
004725-0, 004725-1,
004725-2, 004725-3,

004726-0

Generac®Power Systems, Inc.

INTRODUCTION

Thank you for purchasing this model of the standby
generator set product line by Generac Power Systems.

Every effort was expended to make sure that the
information and instructions in this manual are both
accurate and current at the time the manual was writ­ten. However, the manufacturer reserves the right to
change, alter or otherwise improve this product(s) at
any time without prior notice.

READ THIS MANUAL THOROUGHLY

If any portion of this manual is not understood, 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 service or
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 personal injury
or property damage.

After this heading, read instructions that, if not
strictly complied with, may result in 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 is as 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.

The operator is responsible for proper and safe use
of the equipment. Generac strongly recommends that
the operator read this Owner's Manual and thor­oughly understand all instructions before using this
equipment. Generac also strongly recommends
instructing other users to properly start and operate
the unit. This prepares them if they need to operate
the equipment in an emergency.

OPERATION AND MAINTENANCE

It is the operator'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/operator 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. See a Generac Authorized
Service Dealer for service aids and accessories.

Operating instructions presented in this manual
assume that the standby electric system has been
installed by a Generac Authorized Service Dealer or
other competent, qualified contractor. Installation of
this equipment is not a “do-it-yourself” project.

HOW TO OBTAIN SERVICE

When the generator requires servicing or repairs,
contact a Generac Authorized Service Dealer for
assistance. Service technicians are factory-trained
and are capable of handling all of servicing needs.

When contacting a Generac Authorized Service
Dealer about parts and service, always supply the
complete model number of the unit as given on the
front cover of this manual or on the DATA LABEL
affixed to the unit.

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AUTHORIZED SERVICE

DEALER LOCATION

To locate the nearest GENERAC AUTHORIZED

SERVICE DEALER, please call this number:

1-800-333-1322

OR

Locate us on the web at:

www.generac.com

DANGER

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Table of Contents

Guardian Liquid-cooled 15 kW, 20 kW and 25 kW Generators

Generac®Power Systems, Inc. 1

INTRODUCTION ..................................IFC

SAFETY RULES ......................................2

Section 1 — GENERAL

INFORMATION..................4

1.1 Generator ......................................................4

1.2 Transfer Switch ............................................4

1.3 Automatic System Operation ........................4

1.4 Generator AC Connection Systems................4

1.5 Main Circuit Breaker ....................................4

1.6 Generator Fuel System ..................................4

1.7 Engine Protective Devices ..............................5

1.8 Unpacking ....................................................6

1.9 Lifting the Generator ....................................6

1.10 Specifications ................................................7

1.11 Fuel Consumption ........................................7

1.12 Reconfiguring the Fuel System ......................7

1.13 Torque Specifications ....................................8

1.14 Engine Oil Recommendations ......................8

1.15 Coolant Recommendations............................8

1.16 Before Installation ........................................8

Section 2 — INSTALLATION ................8

2.1 Standby Generator Installation ....................8

2.2 Generator Location ......................................9

2.3 Generator Mounting and Support ................9

2.4 Basic Standby Electric System ......................9

2.5 Emergency Circuit Isolation Method ..........10

2.6 Total Circuit Isolation Method ....................10

2.7 Grounding the Generator ............................10

2.8 Generator AC Neutral Connections ............10

2.9 Transfer Switch Start Signal Connections ..10

2.10 Battery Installation ......................................11

2.11 Preparation Before Start-Up........................11

Section 3 — OPERATION....................12

3.1 Using a Standard “GTS” Transfer Switch....12

3.2 Control Console Components......................12

3.3 Manual Transfer and Startup......................13

3.4 Automatic Operation ..................................13

3.5 Weekly Exercise Cycle..................................13

3.6 Engine Heater..............................................14

Section 4 — MAINTENANCE ..............14

4.1 Maintenance Performed by Authorized

Service Facilities ..........................................14

4.2 Cooling System............................................15

4.3 Overload Protection for Engine DC

Electrical System ........................................15

4.4 Checking Fluid Levels ................................15

4.5 Maintenance Owner/Operator

Can Perform................................................15

4.6 Miscellaneous Maintenance ........................17

4.7 Scheduled Maintenance ..............................19

Section 5 — TROUBLESHOOTING......22

5.1 Troubleshooting Points................................22

Section 6 — NOTES............................23

Section 7 — INSTALLATION

DIAGRAM ......................25

Section 8 — ELECTRICAL DATA ........26

Section 9 — EXPLODED VIEWS AND

PARTS LISTS ................30

Section 10 — WARRANTY .................48

2 Generac®Power Systems, Inc.

Study these SAFETY RULES carefully before installing,
operating or servicing this equipment. Become familiar
with this Owner’s 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 possible
cirumstance 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 that
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 install, 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.

GENERAL HAZARDS

• For safety reasons, Generac recommends that this
equipment be installed, serviced and repaired by a
Generac Authorized Service Dealer or other compe­tent, qualified electrician or installation technician
who is familiar with applicable codes, standards and
regulations. The operator also must comply with all
such codes, standards and regulations.

• Installation, operation, servicing and repair of this
(and related) equipment must always 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, operated and serviced in accordance
with the manufacturer’s instructions and recommen­dations. Following installation, do nothing that might
render the unit unsafe or in noncompliance with the
aforementioned codes, standards, laws and regula­tions.

• The engine exhaust fumes contain carbon monoxide
gas, which can be DEADLY. This dangerous gas, if
breathed in sufficient concentrations, can cause
unconsciousness or even death. For that reason, ade­quate ventilation must be provided. Exhaust gases
must be piped safely away from any building or
enclosure that houses the generator to an area where
people, animals, etc., will not be harmed. This
exhaust system must be installed properly, in strict
compliance with applicable codes and standards.

• 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 ventilat­ing air is critical to prevent buildup of explosive gases
and to ensure correct generator operation. Do not
alter the installation or permit even partial blockage
of ventilation provisions, as this can seriously affect
safe operation of the generator.

• Keep the area around the generator clean and unclut­tered. Remove any materials that could become haz­ardous.

• When working on this equipment, remain alert at all
times. Never work on the equipment when physically
or mentally fatigued.

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IMPORTANT SAFETY INSTRUCTIONS

Guardian Liquid-cooled 15 kW, 20 kW and 25 kW Generators

SAVE THESE INSTRUCTIONS – The manufacturer suggests that these rules for safe
operation be copied and posted in potential hazard areas. Safety should be stressed to all
operators, potential operators, and service and repair technicians for this equipment.

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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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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:

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DANGER

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Generac®Power Systems, Inc. 3

• Inspect the generator regularly, and promptly repair
or replace all worn, damaged or defective parts using
only factory-approved parts.

• 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.

ELE

CTRICAL HAZARDS

• All generators covered by this manual produce dan­gerous electrical voltages and can cause fatal electrical
shock. Utility power delivers extremely high and dan­gerous voltages to the transfer switch as well as the
standby generator. Avoid contact with bare wires, ter­minals, connections, etc., on the generator as well as
the transfer switch, if applicable. 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.

• If people must stand on metal or concrete while
installing, operating, servicing, adjusting or repairing
this equipment, place insulative mats over a dry
wooden platform. Work on the equipment only while
standing on such insulative mats.

• The National Electrical Code (NEC), Article 250
requires the frame and external electrically conduc­tive parts of the generator to be connected to an
approved earth ground and/or grounding rods. This
grounding will help prevent dangerous electrical
shock that might be caused by a ground fault condi­tion in the generator set or by static electricity. Never
disconnect the ground wire.

• Wire gauge sizes of electrical wiring, cables and cord
sets must be adequate to handle the maximum elec­trical current (ampacity) to which they will be sub­jected.

• Before installing or servicing this (and related) equip­ment, make sure that all power voltage supplies are
positively turned off at their source. Failure to do so
will result in hazardous and possibly fatal electrical
shock.

• Connecting this unit to an electrical system normally
supplied by an electric utility shall be by means of a
transfer switch so as to isolate the generator electric
system from the electric utility distribution system
when the generator is operating. Failure to isolate the
two electric system power sources from each other by
such means will result in damage to the generator
and may also result in injury or death to utility power
workers due to backfeed of electrical energy.

• Generators installed with an automatic transfer
switch will crank and start automatically when nor­mal (utility) source voltage is removed or is below an
acceptable preset level. To prevent such automatic
start-up and possible injury to personnel, disable the
generator’s automatic start circuit (battery cables,
etc.) before working on or around the unit. Then,
place a “Do Not Operate” tag on the generator control
panel and on the transfer switch.

• 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.

F

IRE HAZARDS

• Keep a fire extinguisher near the generator at all
times. Do NOT use any carbon tetra-chloride type
extinguisher. Its fumes are toxic, and the liquid can
deteriorate wiring insulation. Keep the extinguisher
properly charged and be familiar with its use.
Consult the local fire department for any questions
pertaining to fire extinguishers.

EXPLOSION HAZARDS

• Properly ventilate any room or building housing the
generator to prevent build-up of explosive gas.

• Do not smoke around the generator. Wipe up any fuel
or 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.

• Generac generator sets may operate using one of sev­eral types of fuels. All fuel types are potentially FLAM­MABLE and/or EXPLOSIVE and should be handled
with care. Comply with all laws regulating the storage
and handling of fuels. Inspect the unit’s fuel system
frequently and correct any leaks immediately. Fuel
supply lines must be properly installed, purged and
leak tested according to applicable fuel-gas codes
before placing this equipment into service.

• Diesel fuels are highly FLAMMABLE. Gaseous fluids
such as natural gas and liquid propane (LP) gas are
extremely EXPLOSIVE. Natural gas is lighter than air,
and LP gas is heavier than air. Install leak detectors
accordingly.

IMPORTANT SAFETY INSTRUCTIONS

Guardian Liquid-cooled 15 kW, 20 kW and 25 kW Generators

4 Generac®Power Systems, Inc.

1.1 GENERATOR

This equipment is a liquid-cooled, engine-driven gen­erator set. The generator is designed to supply elec­trical power that operates critical electrical loads
during utility power failure. The unit has been facto­ry-installed in a weather resistant, all metal enclosure
and is intended for outdoor installation only. Use this
generator as a source of electrical power for the oper­ation of 120 and/or 240 volts, single phase loads.

These models are available. They are rated as follows:

Models 0047210 and 0047220: Provides 15,000
watts (15 kW) of single phase power.

Models 0047230 and 0047240: Provides 20,000
watts (20 kW) of single phase power.

Models 0047250, 0047251, 0047252, 0047253,
and 0047260: Provides 25,000 watts (25 kW) of sin-

gle phase power.

If this generator is used to power electrical
load circuits normally powered by a utility
power source, it is required by code to install
a transfer switch. The transfer switch must
effectively isolate the electric system from the
utility distribution system when the generator
is operating (NEC 701). Failure to isolate an
electrical system by such means results in
damage to the generator and may also result
in injury or even death to utility power work­ers due to backfeed of electrical energy.

1.2 TRANSFER SWITCH

This generator system may include a matched auto­matic transfer switch which is intended to be used in
conjunction with the Guardian generator. It is sup­plied in either a NEMA 1 enclosure (15 kW model
004721, 20 kW models 004723) or a NEMA 3R
enclosure (25 kW models 004725). The NEMA 1
enclosure is intended for indoor use only. The NEMA
3R enclosure is weather proof and can be used
indoors or outdoors. Follow these rules:

• Install the transfer switch on a firm, sturdy sup­porting structure.

• To prevent switch distortion, level the switch if nec­essary. This can be done by placing washers
between the switch enclosure and the mounting
surface.

• Never install the switch where water or any corro­sive substance might drip onto the enclosure.

• Protect the switch at all times against excessive
moisture, dust, dirt, lint, construction grit and cor­rosive vapors.

• Failure to utilize a Generac/Guardian transfer
switch with this generator will void the warranty.

1.3 AUTOMATIC SYSTEM OPERATION

When this generator, along with its transfer switch, has
been installed and interconnected, a circuit board in
the generator panel constantly monitors utility power
source voltage. Should that voltage drop below a pre­set value, and remain at such a low state for a preset
amount of time, the generator cranks and starts. After
the generator starts, the transfer switch transfers load
circuits so the generator can power them.

When utility source voltage has been restored, the
switch re-transfers back to the utility source voltage
and the generator then shuts down.

Please reference the transfer switch manual for spe­cific information.

1.4 GENERATOR AC CONNECTION
SYSTEMS

The generator was shipped from the factory with its
stator AC output leads connected in a single-phase,
three-wire generator AC connection system (Figure

1.1). The stator assembly in this system consists of a

pair of stationary windings, with two leads brought
out of each winding. Each single winding can supply
120 volts AC, 60 Hertz. When the two windings are
connected in series, a 240 volts, 60 Hertz AC output
results. Typically the two “hot” leads in the circuit are
Wires No. 11 and 44. The “Neutral” leads are the
junction of Wires 22 and 33.

Figure 1.1 - Generator AC Connection System

1.5 MAIN CIRCUIT BREAKER

The generator’s main circuit breaker is included with
the unit as shipped from the factory. The breaker for
each unit is described in Figure 1.2 at the top of page

5.

1.6 GENERATOR FUEL SYSTEM

The generator has been factory tested and adjusted
using a natural gas fuel system. If propane (LP
requirements) gas is preferred, contact an authorized
service dealer. Refer to Secion 1.12.

Section 1 - General Information

Guardian Liquid-cooled 15 kW, 20 kW and 25 kW Generators

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Generac®Power Systems, Inc. 5

Recommended fuels should have a Btu content of at
least 1,000 Btus per cubic foot for natural gas and at
least 2,520 Btus per cubic foot for LP gas. Ask the
fuel supplier for the Btu content of the fuel being
used.

Fuel pressure for both natural gas and liquid
propane set ups should be 11 inches to 14 inches

of water column (0.6 psi) at all load ranges.

NOTE:

A seperate gas line and regulator may be needed
to assure proper gas pressure (11-14”) to the gen­erator. Low gas pressure can cause hard starting
and could affect engine durability.

Gaseous fuels such as natural and LP
(propane) gas are highly explosive. Even the
slightest spark can ignite such fuels and cause
an explosion. No leakage of fuel is permitted.
Natural gas, which is lighter than air, tends to
collect in high areas. LP gas is heavier than air
and tends to settle in low areas.

1.7 ENGINE PROTECTIVE DEVICES

The engine has several safety switches which cause
the engine to automatically shut down under the fol­lowing conditions: low oil pressure, high coolant tem­perature, engine overspeed, low coolant level or over­crank (Figure 1.3).

Figure 1.3 - Engine Protective Devices

1.7.1 LOW OIL PRESSURE SWITCH

This switch is normally-closed (N.C.), but is held
open by engine oil pressure during engine running.
Should operating oil pressure drop below about 8-10
psi (55-68 kPa), the switch contacts close and the
engine shuts down automatically (Figure 1.4).

Figure 1.4 - Low Oil Pressure Switch

1.7.2 HIGH COOLANT TEMPERATURE SWITCH

This normally open (N.O.), thermostatic switch has
sensing tip which is immersed in captive coolant.
Should coolant temperature exceed about 230°F
(110°C), the switch contacts close, which causes the
engine to shut down automatically (Figure 1.5).

Figure 1.5- High Coolant Temperature Switch

1.7.3 LOW COOLANT LEVEL SWITCH

Should engine coolant level drop below the level of
the high coolant temperature switch, it is possible for
the engine to overheat without automatic shutdown.
To prevent such overheating without automatic shut
down, the engine has a low coolant level sensor. If the
engine coolant drops too low, the engine automatical­ly shuts down (Figure 1.6 on page 6).

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Section 1 - General Information

Guardian Liquid-cooled 15 kW, 20 kW and 25 kW Generators

Model Rating Phase Actual Current C/B Rating* % over rating Circuit Breaker

004721/004722 15,000 1 62.5 70 112% 70A BQ2
004723/004724 20,000 1 83.3 90 108% 90A BQ2
004725/004726 25,000 1 104.2 125 120% 125A BQ2

* Amp Rating of CB structured under model.

Figure 1.2 - Main Circuit Breaker

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6 Generac®Power Systems, Inc.

Figure 1.6 - Low Coolant Level Sensor

1.7.4 OVERSPEED SHUTDOWN

The Pre-pack circuit board on liquid cooled units
receives AC frequency (rpm) signals directly from the
stator AC power windings, via sensing leads S15 and
S16. Should AC frequency exceed about 72 Hz, cir­cuit board action will automatically shutdown the
engine (Figure 1.7).

*Rated power of generator is subject to and limit­ed by such factors as ambient temperature, alti­tude, engine condition, and other factors. Engine
power will decrease about 3.5% for each 1000 feet
above sea level and will decrease an additional 1%
for each 10°F above 60°F. Maximum output power
of the generator is limited by maximum engine
power.

Figure 1.7 - Control Module Assembly

Circuit Board

1.7.5 PCB OPERATION LED’S

• LED 1 is RED. The LED is on when utility sensing
is NOT available to the circuit board. This LED will
function only when the Auto/Off/Manual switch is
set in the Auto position.

• LED 2 is YELLOW. This LED is on when the circuit
board battery charger is on. This LED will cycle on
and off with the battery charger, 4.85 hours on the

4.85 hours off.

• LED 3 is GREEN. This LED will flash when the cir­cuit board has load voltage available to it. This
LED will function when voltage is available across
T1 and T2.

1.7.6 OVERCRANK SHUTDOWN

After 90 seconds of crank-rest cycles, this function
ends cranking if the engine fails to start in that
90-second span.

1.7.6 DC FUSE

This clearly labeled fuse is located on the front panel
of the control system. It protects the panel wiring and
components from damaging overload. Always

remove this fuse before commencing work on the
generator. The unit will not start or crank if the fuse

is blown. Replace the fuse with one of the same size,
type, and rating. Generac normally uses an AGC fuse
rated at 15 amps (part number 022676).

1.8 UNPACKING

1.8.1 UNPACKING PRECAUTIONS

Handle shipping cartons and crates with care. Use
care to avoid damage from dropping, bumping, colli­sion, etc. Store and unpack cartons with the proper
side up, as noted on the shipping carton.

1.8.2 INSPECTION

After unpacking, carefully inspect the generator for
any damage that may have occurred during ship­ment. If loss or damage is noted at the time of deliv­ery, have the person(s) making delivery note all dam­age on the freight bill or affix their signature under
the consignor’s memo of loss or damage.

1.9 LIFTING THE GENERATOR

When lifting or hoisting equipment is used,
be careful not to touch overhead power lines.
The generators weight of more than 900
pounds requires proper tools, equipment, and
qualified personnel to be used in all phases of
handling and unpacking.

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Section 1 — General Information

Guardian Liquid-cooled 15 kW, 20 kW and 25 kW Generators

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7

LED

R2

R3

R1

R1

R1

3

2

3

R1

3

4

4

2

6

8

8

8

T R

FOR 50H

M1

5

M1

R1

6

8

R4

R3

R3

M

R3

6

R

1

1

1

R2

5

R2

R2

K

7

6

8

R

2002 GENERAC POWER SYSTEMS, ASSY #076009

1.10 SPECIFICATIONS

1.10.1 GENERATOR SPECIFICATIONS

1.10.2 ENGINE SPECIFICATIONS

Make..............................................................................Mitsubishi

Displacement ..............................................92 inches

3

(1.5 liters)

Cylinder Arrangement......................................................4, in-line

Valve Arrangement................................................Overhead Cam

Firing Order........................................................................1-3-4-2

Number of Main Bearings............................................................5

Compression Ratio ..............................................................9 to 1

No. of Teeth on Flywheel ........................................................104

Ignition Timing

at 1800 rpm ..................................................35 degrees BTDC

at 3600 rpm ..................................................43 degrees BTDC

Spark Plug Gap ..................................................0.020-0.025 inch

Recommended Spark Plugs

Champion ....................................................................RN11YC4

Oil Pressure....................................................................30-50 psi

Crankcase Oil Capacity........................3.0 U.S. quarts (2.8 liters)

Recommended Engine Oil........................................SAE 15W-40

Type of Cooling System ..................Pressurized, closed recovery

Cooling Fan ..............................................................Pusher Type

Cooling System Capacity ......................2 U.S. gallons (7.6 liters)

Recommended Coolant ............................Use a 50-50 mixture of

ethylene glycol base.

1.11 FUEL CONSUMPTION

25 kW Models

Using Natural Gas ........................................441 cu. ft. per hour

Using LP Gas ..............................175 cubic ft.(4.8 gal.) per hour

20 kW Models

Using Natural Gas ........................................359 cu. ft. per hour

Using LP Gas ............................143 cubic ft. (4.0 gal.) per hour

15 kW Models

Using Natural Gas ........................................277 cu. ft. per hour

Using LP Gas ..............................110 cubic ft.(3.1 gal.) per hour

NOTE:

Fuel consumption is given at rated maximum con­tinuous power output when using natural gas
rated at 1000 Btu per cubic foot and LP gas rated
2520 Btu per cubic foot. Actual fuel consumption
obtained may vary depending on such variables as
applied load, ambient temperature, engine condi­tions and other environmental factors.

Fuel pressure for both natural gas and liquid
propane set ups should be 11 inches to 14 inches

of water column (0.6 psi) at all load ranges.

NOTE:

A seperate gas line and regulator may be needed
to assure proper gas pressure (11-14”) to the gen­erator. Low gas pressure can cause hard starting
and could affect engine durability.

1.12 RECONFIGURING THE FUEL
SYSTEM

NOTE:

All models are configured for natural gas from the
factory.

To reconfigure the fuel system from NG to LP, follow
these steps:

1. Turn the main gas supply off.

2. Remove the carburetor fuel hose from the outlet

port (Port 1) of the demand regulator (Figure

1.8).

3. Remove the brass hose fitting from the outlet port

(Port 1) of the demand regulator.

4. Remove pipe plug from Port 2.

5. Install brass hose fitting into Port 2.

6. Install pipe plug into Port 1.

7. Connect carburetor gas hose to brass fitting.

8. Tighten all clamps and plugs.

9. Make sure fuel supply is of the proper pressure

and type for configuration.

10. Reverse the procedure to convert back to natural

gas.

Figure 1.8 — Reconfigure the Fuel System

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Section 1 — General Information

Guardian Liquid-cooled 15 kW, 20 kW and 25 kW Generators

Generac®Power Systems, Inc. 7

Single-Phase

Model 004725 004723 004721

004726 004724 004722

Rated Max. Cont. 25 20 15
AC Power Output (kW)
Rated voltage (volts) 120/240
No. of Rotor Poles 2 4
Driven Speed of Rotor 3600 3600 1800
Rotor Excitation System Direct excited brush type
Type of Stator 4 Wire
Rotor/Stator Insulation Class F

Port 2

LP FUEL SYSTEM

PLUG

Port 1

NG FUEL SYSTEM

FUEL HOSE

BRASS HOSE
FITTING

PORT 1

HOUSING
PORTS

FUEL HOSE

BRASS HOSE
FITTING

OUT

OUT
PORT 2

HOUSING
PORTS

PLUG

8 Generac®Power Systems, Inc.

NOTE:

Port 1 is for NG only and Port 2 is for LP vapor
only. No provision for simultaneous fuels has been
made.

Serious injury or damage may occur if not con­figured properly. Please consult an authorized
Generac Service Dealer with any questions.

1.13 TORQUE SPECIFICATIONS

Cylinder Head ............................................15 (+ 90° + 90°) ft.lb.

Intake Manifold ................................................................13 ft.lb.

Exhaust Manifold..............................................................13 ft.lb.

1.14 ENGINE OIL RECOMMENDATIONS

The unit has been filled with 15W-40 engine oil at the
factory. Use a high-quality detergent oil classified “For
Service CC, SD, SE, SF.” Detergent oils keep the engine
cleaner and reduce carbon deposits. Use oil having the
following SAE viscosity rating, based on the ambient
temperature range anticipated before the next oil
change:

Any attempt to crank or start the engine before
it has been properly serviced with the recom­mended oil may result in an engine failure.

1.15 COOLANT RECOMMENDATIONS

Use a mixture of half low silicate ethylene glycol base
anti-freeze and deionized water. Cooling system
capacity is about 8 U.S. quarts (7.6 liters). Use only
deionized water and only low silicate anti-freeze. If
desired, add a high quality rust inhibitor to the rec­ommended coolant mixture. When adding coolant,
always add the recommended 50-50 mixture.

Do not use any chromate base rust inhibitor
with ethylene glycol base anti-freeze or chromi­umhydroxide (“green slime”) forms and will
cause overheating. Engines that have been
operated with a chromate base rust inhibitor
must be chemically cleaned before adding eth­ylene glycol base anti-freeze. Using any high
silicate anti-freeze boosters or additives will
also cause overheating. Generac Power Systems
also recommends that any soluble oil inhibitor
is NOT used for this equipment.

1.16 BEFORE INSTALLATION

Before installing this equipment, check the ratings of
both the generator and the transfer switch. Read
“Emergency Isolation Method” and “Total Circuit
Isolation Method” in the installation manual (Part No.

079699).

The generator’s rated wattage/amperage capacity
must be adequate to handle all electrical loads that
the unit will power. The critical (essential) loads may
need to be grouped together and wired into a sepa­rate “emergency” distribution panel.

This generator can be installed in conjunction with a
standard Generac “GTS” type transfer switch, if
desired.

The standard transfer switch has no sensing or con­trolling circuit boards. Instead, the generator control
console houses a “Printed Circuit Board Assembly”,
which controls all phases of operation, including
engine start up and load transfer.

2.1 STANDBY GENERATOR
INSTALLATION

Connecting this generator to an electrical sys­tem normally supplied by an electric utility
shall be by means of a transfer switch, so as
to isolate the electric system from the utility
distribution system when the generator is
operating. Failure to isolate the electric sys­tem by these means will result in damage to
the generator and may also result in injury or
death to utility workers due to backfeed of
electrical energy.

If an open bottom is used, the engine-genera­tor is to be installed over non-combustible
materials and should be located such that com­bustible materials are not capable of accumu­lating under the generator set.

Only qualified, competent installation contractors or
electricians thoroughly familiar with applicable
codes, standards and regulations should install this
standby electric power system. The installation must
comply strictly with all codes, standards and regula­tions pertaining to the installation.

This genset must be installed on a level surface. The
base frame must be level within 1/2 inch all around.

After the system has been installed, do nothing
that might render the installation in noncompli­ance with such codes, standards and regula­tions.

!

Section 2 — Installation

Guardian Liquid-cooled 15 kW, 20 kW and 25 kW Generators

Temperature Oil Grade (Recommended)

Above 80° F (27° C) SAE 30W or 15W-40

32° to 80° F (-1° to 27° C) SAE 20W-20 or 15W-40

Below 32° F (0° C) SAE 10W or 15W-40

DANGER

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!

DANGER

Generac®Power Systems, Inc. 9

NOTE:

For more information about the installation of a
standby system, order Engine-Generator Standby

Electric Power Systems Installer’s Guide and
Reference Manual (part #046622) from a Generac

Authorized Service Dealer.

2.1.1 NFPA STANDARDS

The following published standards booklets pertain­ing to standby electric systems are available form the
National Fire Protection Association (NFPA),
Batterymarch Park, Quincy, MA 02269:

• NFPA No. 37, STATIONARY COMBUSTION
ENGINES AND GAS TURBINES.

• NFPA No. 76A, ESSENTIAL ELECTRICAL SYS­TEMS FOR HEALTH CARE FACILITIES.

• NFPA No. 220, STANDARD TYPES OF BUILDING
CONSTRUCTION

• NFPA No. 68, GUIDE FOR EXPLOSION VENTING

• NFPA No. 70, NATIONAL ELECTRICAL CODE.

• NFPA No. 30, FLAMMABLE AND COMBUSTIBLE
LIQUIDS CODE.

• NFPA No. 10, INSTALLATION, MAINTENANCE AND
USE OF PORTABLE FIRE EXTINGUISHERS.

2.1.2 OTHER PUBLISHED STANDARDS

In addition to NFPA standards, the following infor­mation pertaining to the installation and use of
standby electric systems is available:

• Article X, NATIONAL BUILDING CODE, available
from the American Insurance Association, 85 John
Street, New York, N.Y. 10038.

• AGRICULTURAL WIRING HANDBOOK, obtainable
from the Food and Energy Council, 909 University
Avenue, Columbia, MO, 65201.

• ASAE EP-364.2, INSTALLATION AND MAINTE­NANCE OF FARM STANDBY ELECTRIC POWER,
available from the American Society of Agricultural
Engineers, 2950 Niles Road, St. Joseph, MI 49085.

• A52.1, AMERICAN NATIONAL STANDARD FOR
CHIMNEYS, FIREPLACES AND VENTING SYS­TEMS, available from the American National
Standard Institute, 1430 Broadway, New York, N.Y.

10018.

2.2 GENERATOR LOCATION

Install the generator set, in its protective enclosure
outdoors, where adequate cooling and ventilating air
always is 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 five feet of space on all sides.

• Where strong prevailing winds blow from one
direction, face the generator air inlet openings into
the prevailing winds.

• Install the generator as close as possible to the
transfer switch. This reduces the length of wiring
and conduit.

• Install the generator as close as possible to the fuel
supply, to reduce the length of piping. HOWEVER,
REMEMBER THAT LAWS OR CODES MAY REG­ULATE THE DISTANCE.

2.3 GENERATOR MOUNTING AND

SUPPORT

Retain the generator compartment to a concrete slab
with 1/4-inch masonry type anchor bolts. Be sure the
bolts are long enough to retain the compartment. The
slab should be at least six inches thick and should
extend beyond the enclosure to a distance of at least
three inches on all sides. See Section 7, Installation
Diagram.

2.4 BASIC STANDBY ELECTRIC

SYSTEM

Figure 2.1 shows a schematic diagram of a basic
standby electric system. Both the UTILITY power
supply and the STANDBY (generator) output are con­nected to an approved transfer switch. The transfer
switch is required by electrical code and serves the
following functions:

• Permits the LOAD circuits to be connected to only
one power supply at a time.

• Prevents electrical backfeed between the generator
and the UTILITY power circuits.

Notice that both the STANDBY and the UTILITY
power supplies to the transfer switch are protected
against overload by a main line circuit breaker.

Figure 2.1 – Basic Standby Electric System

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Section 2 — Installation

Guardian Liquid-cooled 15 kW, 20 kW and 25 kW Generators

10 Generac®Power Systems, Inc.

NOTE:

Generac recommends the use of a Generac Power
Systems “GTS” type transfer switch in conjunc­tion with this generator.

2.5 EMERGENCY CIRCUIT ISOLATION
METHOD

This prevents overloading the generator by keeping
electrical loads below the wattage/amperage capacity
of the generator. If the generator is powering only crit­ical loads, within the wattage/amperage capacity, dur­ing utility power outages, consider using the emer­gency circuit isolation method.

Critical electrical loads are grouped together and
wired into a separate “Emergency Distribution
Panel.” Load circuits powered by that panel are with­in the wattage/amperage capacity of the generator set.
When this method is used, it is difficult to overload
the generator. The transfer switch must meet the fol­lowing requirements:

• It must have an ampere rating equal to, or greater

than, the total amperage rating of the emergency
distribution panel circuit.

• Have it installed between the building’s main dis-

tribution panel and the emergency distribution
panel.

2.6 TOTAL CIRCUIT ISOLATION
METHOD

When a generator capable of powering all electrical
loads in the circuit is to be installed, use the “Total
Circuit Isolation Method.” It is possible for the gener­ator to be overloaded when this isolation method is
employed. The following apply to the transfer switch
in this type of system.

• Ampere rating of the transfer switch must be equal

to, or greater than, the ampere rating of the normal
incoming utility service.

• The transfer switch is installed between the utility

service entrance and the building distribution
panel.

2.7 GROUNDING THE GENERATOR

The National Electrical Code requires the frame and
external electrically conductive parts of this equip­ment to be properly connected to an approved earth
ground and/or grounding rods. For that purpose, a
GROUND LUG (Figure 2.2) is provided on the gener­ator mounting base. Consult a qualified electrician
for grounding requirements in the area. Grounding
procedures must meet local regulations.

Do not connect the ground wire to any pipe
that carries a flammable or explosive substance
– FIRE or an EXPLOSION may result.

Proper grounding helps protect personnel against
electrical shock in the event of a ground fault condi­tion in the generator or in connected electrical
devices. In addition, grounding helps dissipate static
electricity that often builds up in ungrounded
devices.

Figure 2.2 – Generator Grounding Lug (typical)

2.8 GENERATOR AC NEUTRAL
CONNECTIONS

Generac Power Systems uses an UNGROUNDED AC
neutral. Grounding is recommended only at the main
service entrance. If the neutral wire is grounded and
one of the phase loads becomes grounded, the exces­sive current opens the load circuit breaker or col­lapses the generator field. The actual result depends
on the electrical characteristics of the particular
installed generator.

2.9 TRANSFER SWITCH START SIGNAL
CONNECTIONS

If the generator is to be installed with an automatic
transfer switch, such as a Generac GTS-type switch,
it is necessary to connect the two-wire start
control system.

Connect the two-wire start signal from the automatic
transfer switch to the automatic start connection,
which is located in the right hand corner inside the
control panel. Match wires 178 and 183 in the trans­fer switch to 178 and 183 on the terminal strip in the
control panel. The conductors for the two-wire start
circuit must be in their own conduit.

Section 2 — Installation

Guardian Liquid-cooled 15 kW, 20 kW and 25 kW Generators

DANGER

Generac®Power Systems, Inc. 11

2.10 BATTERY INSTALLATION

Standby generators installed with automatic
transfer switches will crank and start automati­cally when NORMAL (UTILITY) source voltage is
removed or is below an acceptable preset level.
To prevent such automatic start-up and possible
injury to personnel, do not connect battery
cables until the NORMAL source voltage at the
transfer switch is correct and the system is
ready to be put into operation.

Storage batteries give off explosive hydrogen
gas. This gas can form an explosive mixture
around the battery for several hours after
charging. The slightest spark can ignite the gas
and cause an explosion. Such an explosion can
shatter the battery and cause blindness or
other injury. Any area that houses a storage
battery must be properly ventilated. Do not
allow smoking, open flame, sparks or any spark
producing tools or equipment near the battery.

Battery electrolyte fluid is an extremely caustic
sulfuric acid solution that can cause severe
burns. Do not permit fluid to contact eyes, skin,
clothing, painted surfaces, etc. Wear protective
goggles, protective clothing and gloves when
handling a battery. If the fluid is spilled, flush
the affected area immediately with clear water.

Do not dispose of the battery in a fire. The bat­tery is capable of exploding.

Do not open or mutilate the battery. Released
electrolyte can be toxic and harmful to the skin
and eyes.

The battery represents a risk of high short cir­cuit current. When working on the battery,
always remove watches, rings or other metal
objects, and only use tools that have insulated
handles.

2.10.1 VENTED BATTERIES

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) of water. The
bicarbonate of soda solution is to be added until
the evidence of reaction (foaming) has 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 procedure are to be followed:

• DO NOT SMOKE when near batteries,

• DO NOT cause flame or spark in battery area, and

• Discharge static electricity from body before touch­ing batteries by first touching a grounded metal
surface.

Servicing of batteries is to be performed or super­vised by personnel knowledgeable of batteries and
the required precautions. Keep unauthorized person­nel away from batteries.

For recommended batteries, see “Specifications.” All
batteries must be at 100 percent state-of-charge
before they are installed on the generator.

When using maintenance-free batteries, it is not nec­essary to check the specific gravity or electrolyte level.
Have these procedures performed at the intervals
specified in Section 4, “Maintenance.” A negative
ground system is used. Battery connections are
shown on the wiring diagrams. Make sure all batter­ies are correctly connected and terminals are tight.
Observe battery polarity when connecting batteries
to the generator set.

NOTE:

Damage will result if the battery connections are
made in reverse.

2.11 PREPARATION BEFORE START-UP

The instructions in this section assume that the stand­by generator has been properly installed, serviced,
tested, adjusted and otherwise prepared for use by a
competent, qualified installation contractor. Be sure to
read the “Safety Rules” on Pages 2 and 3, as well as all
other safety information in this manual, before
attempting to operate this (and related) equipment.

2.11.1 PRIOR TO INITIAL START-UP

Prior to initially starting the generator, it must
be properly prepared for use. Any attempt to
crank or start the engine before it has been
properly serviced with the recommended types
and quantities of engine fluids (oil, coolant,
fuel, etc.) may result in an engine failure.

Before starting the generator for the first time, the
installer must complete the following procedures. For
follow-up maintenance information and/or service
intervals, please refer to Section 4, “Maintenance.”

!

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Section 2 — Installation

Guardian Liquid-cooled 15 kW, 20 kW and 25 kW Generators

DANGER

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12 Generac®Power Systems, Inc.

2.11.2 TRANSFER SWITCH

If this generator is used to supply power to any elec­trical system normally powered by an electric utility,
the National Electrical Code requires that a transfer
switch be installed. The transfer switch prevents elec­trical backfeed between two different electrical sys­tems. (For additional information, see the applicable
transfer switch manual for this unit.) The transfer
switch, as well as the generator and other standby
components, must be properly located and mounted
in strict compliance with applicable codes, standards
and regulations.

2.11.3 FUEL SYSTEM

Make sure the fuel supply system to the generator (a)
delivers the correct fuel at the correct pressure and
(b) is properly purged and leak tested according to
code. No fuel leakage is permitted. See
“Specifications” (Section 1.10) for more information.

2.11.4 GENERATOR SET LUBRICATION

Check the engine crankcase oil level before operating
and add oil to the proper level – the dipstick “FULL”
mark. Never operate the engine with the oil level
below the dipstick “ADD” mark. See “Specifications”
(Section 1.10) and “Engine Oil Recommendations”
(Section 1.14).

NOTE:

This engine is shipped from the manufacturer
with 15W-40 oil. This oil should be changed after
30 hours of operation.

2.11.5 ENGINE COOLANT

Have the engine cooling system properly filled with
the recommended coolant mixture. Check the system
for leaks and other problems. See “Specifications”
(Section 1.10) and “Coolant” (Section 1.15).

2.11.6 BELT TENSION

Check the engine fan belt tension and condition prior
to placing the unit into service and at recommended
intervals. Belt tension is correct when a force of
approximately 22 pounds (10 kg), applied midway
between pulleys, deflects the belt about 3/8- to 5/8­inch (10 to 16 mm).

2.11.7 ELECTRICAL SYSTEM

Make sure the generator is properly connected to an
approved earth ground and/or ground rod.

Make sure the generator battery is fully charged, prop­erly installed and interconnected, and ready for use.

Check to ensure that there are no loose electrical con­nections. Restrain any loose wires to keep them clear
of any moving generator set components.

3.1 USING A STANDARD “GTS”

TRANSFER SWITCH

When required, the pre-packaged standby generator
can be installed with a standard Generac “GTS” type
engineered automatic transfer switch.

When a GTS type transfer switch is used, it controls
automatic operation and automatic transfer as fol­lows:

• Solid state circuits in the transfer switch monitor
utility power source voltage.

• When utility source voltage drops below a pre-set
level, transfer switch action closes the circuit. The
engine then cranks and starts as controlled by the
pre-packaged generator’s Control Module circuit
board.

• After the engine starts and when the generator AC
output voltage and frequency have reached a
pre-set value, transfer switch circuits signal the
transfer switch main contacts to actuate to the
“STANDBY” power source side. Generator AC out­put then powers load circuits.

• When the utility power source voltage is restored
above a pre-set level, transfer switch solid state
circuits signal the switch main contacts to move
back to their utility power source side.

• Following re-transfer back to the utility power
source side, transfer switch circuit board action
opens the circuit. Engine then shuts down.

NOTE:

If the generator is installed in conjunction with a
standard GTS type transfer switch, refer to the
applicable transfer switch manual for exact oper­ating parameters and timing sequences.

3.2 CONTROL CONSOLE

COMPONENTS

The components of a liquid-cooled generator control
console (Figure 3.1) are as follows:

Figure 3.1 - Liquid-Cooled Generator Panel

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Section 3 — Operation

Guardian Liquid-cooled 15 kW, 20 kW and 25 kW Generators

HOUR METER

AUTO

MANUAL

OFF

FUSE

15-A
AGC

FAULT

INDICATOR

SET
EXERCISE
TIME

ON

Generac®Power Systems, Inc. 13

3.2.1 HOURMETER

Indicates time the engine-generator has operated, in
hours and tenths of hours. Use the hourmeter along
with the periodic maintenance schedule for the gen­erator set.

3.2.2 AUTO/OFF/MANUAL SWITCH

Use this three-position switch as follows:

• Set the switch to AUTO for fully automatic opera­tion. See “Automatic Operation”, Section 3.4.

• Set switch to MANUAL position to crank and start
the generator engine.

• Set switch to OFF position to shut down an oper­ating engine. With OFF selected, operation will not
be possible.

With switch set to AUTO, engine can crank
and start suddenly without warning. Such
automatic start up normally occurs when utili­ty source voltage drops below a pre-set level.
To prevent possible injury that might be
caused by such sudden starts, set
AUTO/OFF/MANUAL switch to OFF before
working on or around the unit. Then, place a
"DO NOT OPERATE" tag on control console.

3.2.3 FAULT INDICATOR LAMP

The lamp goes ON when one or more of the following
engine faults occurs and when engine shuts down.

• Low oil pressure • Overcrank

• High coolant temperature • Overspeed

• Low coolant level

3.2.4 15 AMP FUSE

The fuse protects the control console’s DC control
circuit against electrical overload. If the fuse has
melted open because of an overload, engine cranking
and startup cannot occur. If replacement of the fuse
is necessary, use only an identical 15-amp fuse. (Type
AGC, part number 022676).

3.2.5 7.5 AMP INLINE FUSE

This inline fuse is connected in the 15A line that runs
between the Auto/Off/Manual switch and position 10
of the 76009A PCB. This fuse protects the start, fuel,
field boost, and transfer outputs from the PCB and
will open if there is excessive current draw on any
one of these outputs.

NOTE:

This fuse will not remove the positive (+) battery
input power from the PCB when it opens. This
means the exercise timer will not be reset. If this
fuse does open, carefully check the wiring to the
start, fuel, field boost and transfer outputs before
replacing the fuse.

3.2.6 SET EXERCISE TIME SWITCH

This switch allows for programming the generator to
start and exercise automatically. See “Weekly
Exercise Cycle” (Section 3.5).

3.3 MANUAL TRANSFER AND
START-UP

To transfer electrical loads to the STANDBY (GEN­ERATOR) power source side and start the engine
manually, refer to the Owner’s Manual of the particu­lar transfer switch.

3.4 AUTOMATIC OPERATION

To set the system for fully automatic operation, pro­ceed as follows:

• Check that load circuits are connected to the

utility power supply.

• Set the AUTO/OFF/MANUAL switch to its AUTO

position.

• Set the generator main circuit breaker to its ON or

CLOSED position.

3.5 WEEKLY EXERCISE CYCLE

The generator will start and exercise once every seven
days. During this weekly exercise, the unit runs for
about 20 minutes and shuts down. Transfer of loads
to generator output does not occur during the exer­cise.

To select day and time for exercising, proceed as
follows:

• Set the AUTO/OFF/MANUAL switch to OFF.

• Set generator main circuit breaker to OFF or

OPEN.

• Locate the rocker switch on the control panel iden-

tified with the words “Set Exercise Time” (Figure

3.2).

• Push “Set Exercise Time” switch to ON position for

20 to 30 seconds and then release. Switch will
spring back into its original position when
released.

• Wait 30 seconds before setting the AUTO/OFF/

MANUAL switch to AUTO position.

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Section 3 - Operation

Guardian Liquid-cooled 15 kW, 20 kW and 25 kW Generators

DANGER

14 Generac®Power Systems, Inc.

If the AUTO/OFF/MANUAL switch is switched
too soon, the engine may start. If engine does
start, it will shut down automatically in about
two (2) minutes.

• Set the generator main circuit breaker to its ON or
CLOSED position.

• Generator is now programmed to start and exer­cise every seven days thereafter, on day and time of
day the switch was actuated.

• Place a sign on the generator control panel and the
transfer switch, indicating the day and time the
generator will be exercising.

NOTE:

If battery terminals are disconnected, the exercise
timer needs to be reset for correct automatic exer­cise operation.

Figure 3.2 - “Set Exercise” Switch

3.6 ENGINE HEATER

This standby generator comes equipped with a block
heater (Figure 3.3), similar to the block heaters used
in automotive applications. The block heater is wired
to a grounded plug.

Figure 3.3 - Engine Block Heater

Refer to applicable wiring diagram(s) and electrical
schematic(s) at back of manual for wiring connec­tions. Customer supplies a 120V 15A Utility fed cir­cuit for the block heater.

4.1 MAINTENANCE PERFORMED BY
AUTHORIZED SERVICE FACILITIES

A. EVERY THREE MONTHS

1.Check battery state of charge and condition.

2.Inspect and test fuel system.

3.Check transfer switch.

4.Inspect exhaust system.

5.Check engine ignition system.

6.Check fan belts.

B. ONCE EVERY SIX MONTHS

1.Test Engine Safety Devices (low oil pressure, low
coolant level, high coolant temperature).

C. ONCE ANNUALLY

1.Test engine governor. Adjust or repair, if needed.

2.Clean, inspect generator.

3.Flush cooling system.

D. FIRST 100 OPERATING HOURS

1.Change engine oil and oil filter. (After initial
change, service engine oil and filter at 150 oper­ating hours or six months, whichever comes
first.)

2.Retorque cylinder head. (See Torque Specs,
Section 1.13.)

3.Retorque intake and exhaust manifold. (See
Torque Specs, Section 1.13.)

E. EVERY 500 OPERATING HOURS

1.Service air cleaner.

2.Check starter.

3.Check engine DC alternator.

F. EVERY 800 OPERATING HOURS

1.Retorque cylinder head. (See Torque Specs,
Section 1.13.)

2.Retorque intake and exhaust manifold. (See
Torque Specs, Section 1.13.)

3.Check engine compression.

4.Check valve clearance.

Section 4 — Maintenance

Guardian Liquid-cooled 15 kW, 20 kW and 25 kW Generators

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