Generac Power Systems MLG15 User manual

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Owner’s Manual
For
Diesel Generator
MLG8 • MLG15 • MLG20 • MLG20ICAN


ii Owner’s Manual for Mobile Generator
(000004)
WARNING
California Proposition 65. Engine exhaust and some
of its constituents are known to the state of California
to cause cancer, birth defects, and other reproductive
harm.
(000005)
WARNING
California Proposition 65. This product contains or
emits chemicals known to the state of California to
cause cancer, birth defects, and other reproductive
harm.

Owner’s Manual for Mobile Generator iii
Table of Contents
Introduction and Safety
Introduction .......................................................1
Read This Manual Thoroughly ..........................1
Safety Rules ......................................................1
General Hazards ...............................................2
Explosion and Fire Hazards ..............................2
Trailer Hazards ..................................................3
Electrical Hazards .............................................3
Battery Hazards ................................................4
General Information
Component Locations .......................................5
Unit and Serial Number Locations ....................6
Engine Oil Recommendations ...........................6
Coolant Recommendation .................................6
Main Control Panels ..........................................7
Operation
Prestart Checklist ..............................................9
Starting the Unit ................................................9
Emergency Stop Switch ..................................10
Automatic Shutdown .......................................10
Voltage Regulator ...........................................11
Derating for Altitude ........................................11
Wet Stacking ...................................................11
Receptacle Panel ............................................11
Shutting Down the Unit ...................................11
Towing the Unit ...............................................11
Lifting the Unit .................................................12
Maintenance
Emissions Information .................................... 13
Daily Walk Around Inspection ......................... 13
General Maintenance ..................................... 13
Basic Maintenance Schedule ......................... 13
Jack Maintenance ........................................... 16
Side-Wind Models ...........................................16
Top-Wind Models ............................................16
Trailer Wheel Bearings ................................... 16
Lower Radiator Hose Heater Option - Use
and Maintenance ............................................ 17
Wiring Diagrams and Service Log
AC Wiring Diagram W/3-30A, 1-50A Outlets .. 19
AC Wiring Panel Options ................................ 20
AC Wiring Diagram - MLG 8 ........................... 21
DC Wiring Diagram - MLG 8 and MLG15 ....... 22
DC Wiring Diagram - MLG 20 ......................... 23
Trailer Harness ............................................... 24
Service Log ..................................................... 25

iv Owner’s Manual for Mobile Generator
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Owner’s Manual for Mobile Generator 1
Introduction and Safety
Section 1 Introduction and Safety
Introduction
Thank you for purchasing a Generac Mobile Products
LLC product. This unit has been designed to provide
high-performance, efficient operation, and years of use
when maintained properly.
The information in this manual is accurate based on
products produced at the time of publication. The
manufacturer reserves the right to make technical
updates, corrections, and product revisions at any time
without notice.
Read This Manual Thoroughly
If any section of the manual is not understood, contact
your nearest Generac Mobile Products Authorized
Dealer, or contact Generac Mobile Products (GMP)
Customer Service at 1-800-926-9768, or
www.generacmobileproducts.com with any questions
or concerns.
The owner is responsible for proper maintenance and
safe use of the equipment. Before installing, operating, or
servicing this generator:
Save these instructions for future reference. This manual
contains important instructions for the generator that
should be followed during installation, operation and
maintenance of the generator and batteries. ALWAYS
supply this manual to any individual that will use this
machine.
Safety Rules
The manufacturer cannot anticipate every possible
circumstance 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 the manufacturer
does not specifically recommend, verify that it is safe for
others. Also make sure the procedure, work method or
operating technique utilized does not render the
equipment unsafe.
Throughout this publication, and on tags and decals
affixed to the unit, 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:
NOTE: Notes contain additional information important to
a procedure and will be found within the regular text of
this manual.
These safety warnings cannot eliminate the hazards that
they indicate. Common sense and strict compliance with
the special instructions while performing the action or
service are essential to preventing accidents.
(000100a)
WARNING
Consult Manual. Read and understand manual
completely before using product. Failure to
completely understand manual and product
could result in death or serious injury.
(000001)
DANGER
Indicates a hazardous situation which, if not avoided,
will result in death or serious injury.
(000002)
WARNING
Indicates a hazardous situation which, if not avoided,
could result in death or serious injury.
(000003)
CAUTION
Indicates a hazardous situation which, if not avoided,
could result in minor or moderate injury.

2Owner’s Manual for Mobile Generator
Introduction and Safety
General Hazards
Explosion and Fire Hazards
Asphyxiation. Running engines produce
carbon monoxide, a colorless, odorless,
poisonous gas. Carbon monoxide, if not
avoided, will result in death or serious injury.
(000103)
DANGER
(000107)
WARNING
Hearing Loss. Hearing protection is
recommended when using this machine.
Failure to wear hearing protection could
result in permanant hearing loss.
(000111)
WARNING
Moving Parts. Keep clothing, hair, and
appendages away from moving parts. Failure
to do so could result in death or serious injury.
(000108)
WARNING
Hot Surfaces. When operating machine, do not
touch hot surfaces. Keep machine away from
combustibles during use. Hot surfaces
could result in severe burns or fire.
WARNING
In case of an emergency, press the
emergency stop button to stop the engine
immediately. Failure to do so could result
in death or serious injury. (000298)
CAUTION
(000291)
Equipment damage. Do not attempt to start or operate
a unit in need of repair or scheduled maintenance.
Doing so could result in serious injury, death, or
equipment failure or damage.
WARNING
WARNING
Risk of injury. Do not operate or service this
machine if not fully alert. Fatigue can impair the
ability to service this equipment and could result
in death or serious injury. (000215)
(000182)
WARNING
CAUTION
(000229)
Equipment or property damage. Do not block
air intake or restrict proper air flow. Doing so
could result in unsafe operation or damage
to unit.
(000105)
DANGER
Explosion and Fire. Fuel and vapors are
extremely flammable and explosive. Add fuel
in a well ventilated area. Keep fire and spark
away. Failure to do so will result in death
or serious injury.
WARNING
Fire risk. Fuel and vapors are extremely
flammable. Do not operate indoors. Doing so
could result in death, serious injury, or
property or equipment damage. (000281)
(000147)
WARNING
Risk of Fire. Unit must be positioned in a
manner that prevents combustible material
accumulation underneath. Failure to do so
could result in death or serious injury.

Owner’s Manual for Mobile Generator 3
Introduction and Safety
Trailer Hazards Electrical Hazards
WARNING
Trailer must be securely coupled to the hitch
and chains correctly attached. Uncoupled or
unchained towing could result in death or serious
injury. (000233)
WARNING
Do not operate this unit while transporting.
Doing so could result in death or serious
injury.
(000231)
(000234a)
WARNING
Crushing hazard. Verify unit is properly secured
and on level ground. An unsecured unit can
suddenly roll or move, causing death or serious
injury.
WARNING
Property or Equipment Damage. Tighten wheel lug
nuts after first 50 miles to factory specifications.
Failure to do so could result in death, serious injury,
property or equipment damage. (000235)
(000145)
DANGER
Electrocution. In the event of electrical accident,
immediately shut power OFF. Use non-conductive
implements to free victim from live conductor. Apply
first aid and get medical help. Failure to do so will
result in death or serious injury.
(000104)
DANGER
Electrocution. Water contact with a power
source, if not avoided, will result in death
or serious injury.
(000144)
DANGER
Electrocution. Contact with bare wires,
terminals, and connections while generator
is running will result in death or serious injury.
(000152)
DANGER
Electrocution. Verify electrical system is
properly grounded before applying power.
Failure to do so will result in death or serious
injury.
(000123)
DANGER
Electrocution. Turn utility supply OFF before
working on utility connections of the transfer
switch. Failure to do so will result in
death or serious injury.
(000150)
DANGER
Electrocution. Never connect this unit to the electrical
system of any building unless a licensed electrician
has installed an approved transfer switch. Failure to
do so will result in death or serious injury.
(000164)
WARNING
Electrical shock. Disconnect battery ground
terminal before working on battery or battery
wires. Failure to do so could result in death
or serious injury.

4Owner’s Manual for Mobile Generator
Introduction and Safety
Battery Hazards
Always recycle batteries in accordance with local laws
and regulations. Contact your local solid waste collection
site or recycling facility to obtain information on local
recycling processes. For more information on battery
recycling, visit the Battery Council International website
at: http://batterycouncil.org
(000188)
DANGER
Electrocution. Do not wear jewelry while
working on this equipment. Doing so will
result in death or serious injury.
(000137a)
WARNING
(000162)
WARNING
Explosion. Do not dispose of batteries in a fire.
Batteries are explosive. Electrolyte solution can cause
burns and blindness. If electrolyte contacts skin or eyes,
flush with water and seek immediate medical attention.
(000163a)
WARNING
Risk of burn. Do not open or mutilate batteries.
Batteries contain electrolyte solution which can
cause burns and blindness. If electrolyte contacts
skin or eyes, flush with water and seek immediate
medical attention.
WARNING
Environmental Hazard. Always recycle batteries at an
official recycling center in accordance with all local
laws and regulations. Failure to do so could result in
environmental damage, death or serious injury.
(000228)

Owner’s Manual for Mobile Generator 5
General Information
Section 2 General Information
Component Locations
Figure 2-1. Component Locations
Table 2-1. Generator Components
AFuel Filler Location (under door) EReceptacle Panel (not available on MLG8 units)
BRadiator Access Panel FGround Studs (2)
CControl Panel Locations (under door) GSafety Chains
DEmergency Stop Switch (on MLG8 units,
switch is located on front panel)
HTongue Jack

C
B
A
G
H
E
D
F

6Owner’s Manual for Mobile Generator
General Information
Unit and Serial Number Locations
See Figure 2-2 to locate the unit ID tag (A) and Vehicle
Identification Number (VIN) tag (B). Important
information, such as the unit model number, serial
number, VIN and tire loading information is found on
these tags. Record the information from these tags so it
is available if the tags are lost or damaged. When
ordering parts or requesting assistance, you may be
asked to provide this information.
Figure 2-2. Unit and Serial Number Locations
Engine Oil Recommendations
To maintain the product warranty, the engine oil should
be serviced in accordance with the recommendations of
this manual.
The engine has been filled with factory engine oil of a
grade recommended by the engine supplier.
Use a high quality detergent oil with an appropriate
classification and viscosity for the engine type and
ambient temperature conditions. Consult your Generac
Mobile Products Authorized Dealer or the applicable
engine service manual for engine oil recommendations.
Coolant Recommendation
Consult your Generac Mobile Products Authorized
Dealer or the applicable engine service manual for
engine coolant recommendations. See table below for
mixtures:
* Maximum freeze protection is at 70%.
003550
A
B
Freezing Point °F (°C) -12
(-24)
-34
(-36)
-54
(-48)
-90
(-67)
Water (% Volume) 60 50 40 30
Anitfreeze (% Volume) 40 50 60 70*
(000149)
DANGER
Risk of poisoning. Do not use mouth to
siphon coolant. Doing so will result in
death or serious injury.
(000154)
WARNING
Risk of burns. Do not open coolant system
until engine has completely cooled.
Doing so could result in serious injury.
(000165)
CAUTION
Do not use any chromate base rust inhibitor with
propylene glycol base antifreeze, boosters or
additives. Doing so will cause overheating.