Guardian 4389 Operating instructions

Models:
4389, 4758 (6 kW NG, 7 kW LP)
4456, 4759 (12 kW NG, 12 kW LP)
4390, 4760 (13 kW, 15 kW LP)
DIAGNOSTIC
REPAIR MANUAL
AUTOMATIC HOME STANDBY GENERATORS
Visit us online at
www.guardiangenerators.com
DIAGNOSTIC
REPAIR MANUAL
AIR-COOLED

PART TITLE
Specifications
1 General Information
2 AC Generators
3 V-Type Prepackaged Transfer Switches
4 DC Control
5 Operational Tests and Adjustments
6 Electrical Data
DIAGNOSTIC
REPAIR MANUAL
Air-cooled, Prepackaged
Automatic Standby
Generators
Models:
04389, 04758 (6 kW NG, 7 kW LP)
04456, 04759 (12 kW NG, 12 kW LP)
04390, 04760 (13 kW NG, 15 kW LP)
TABLE OF CONTENTS
Page 1

TO FIND KNOWN VALUES 1-PHASE 3-PHASE
KILOWATTS (kW) Volts, Current, Power Factor E x I E x I x 1.73 x PF
1000 1000
KVA Volts, Current E x I E x I x 1.73
1000 1000
AMPERES kW, Volts, Power Factor kW x 1000 kW x 1000
E E x 1.73 x PF
WATTS Volts, Amps, Power Factor Volts x Amps E x I x 1.73 x PF
NO. OF ROTOR Frequency, RPM 2 x 60 x Frequency 2 x 60 x frequency
POLES RPM RPM
FREQUENCY RPM, No. of Rotor Poles RPM x Poles RPM x Poles
2 x 60 2 x 60
RPM Frequency, No. of Rotor Poles 2 x 60 x Frequency 2 x 60 x Frequency
Rotor Poles Rotor Poles
kW (required for Motor Horsepower, Efficiency HP x 0.746 HP x 0.746
Motor) Efficiency Efficiency
RESISTANCE Volts, Amperes E E
II
VOLTS Ohm, Amperes I x R I x R
AMPERES Ohms, Volts E E
RR
E = VOLTS I = AMPERES R = RESISTANCE (OHMS) PF = POWER FACTOR
ELECTRICAL FORMULAS
Page 2

SPECIFICATIONS
Page 3
GENERATOR
Models 04389, 04758 Models 04456, 04759 Model 04390, 04760
Rated Max. Continuous Power Capacity (Watts*) 6,000 NG/7,000 LP 12,000 NG/12,000 LP 13,000 NG/15,000 LP†
Rated Voltage 120/240 120/240 120/240
Rated Max. Continuous Load Current (Amps)
120 Volts** 50.0 NG/58.3 LP 100.0 NG/100.0 LP 108.3 NG/125.0 LP
240 Volts 25.0 NG/29.2 LP 50.0 NG/50.0 LP 54.2 NG/62.5 LP
Main Line Circuit Breaker 30 Amp 50 Amp 60 Amp/70 Amp†
Phase 1 1 1
Number of Rotor Poles 2 2 2
Rated AC Frequency 60 Hz 60 Hz 60 Hz
Power Factor 1 1 1
Battery Requirement Group 26/26R Group 26/26R Group 26/26R
12 Volts and 12 Volts and 12 Volts and
350 Cold-cranking 550 Cold-cranking 550 Cold-cranking
Amperes Minimum Amperes Minimum Amperes Minimum
Weight 452 Pounds 470 Pounds 487 Pounds
Output Sound Level @ 23 ft (7m) at full load 68 db (A) 70.5db (A) 71.5 db (A)
Normal Operating Range -20°F (-28.8°C) to 104°F (40°C)
* Maximum wattage and current are subject to and limited by such factors as fuel Btu content, ambient temperature, altitude, engine power and condition, etc. Maximum power decreas-
es about 3.5 percent for each 1,000 feet above sea level; and also will decrease about 1 percent for each 6° C (10° F) above 16° C (60° F) ambient temperature.
** Load current values shown for 120 volts are maximum TOTAL values for two separate circuits. The maximum current in each circuit must not exceed the value stated for 240 volts.
† 15,000 watt with upgrade kit 04578-0. Kit includes power harnesses and 70 amp 2-pole circuit breaker.
ENGINE
Models 04389, 04758 Models 04456, 04759 Models 04390, 04760
Type of Engine GH-410 GT-990 GT-990
Number of Cylinders 1 2 2
Rated Horsepower 14.5 @ 3,600 rpm 26 @ 3,600 rpm 30 @ 3,600 rpm
Displacement 410cc 992cc 992cc
Cylinder Block Aluminum w/Cast Aluminum w/Cast Aluminum w/Cast
Iron Sleeve Iron Sleeve Iron Sleeve
Valve Arrangement Overhead Valves Overhead Valves Overhead Valves
Ignition System Solid-state w/Magneto Solid-state w/Magneto Solid-state w/Magneto
Recommended Spark Plug RC12YC RC12YC RC12YC
Spark Plug Gap 0.76 mm (0.030 inch) 0.5 mm (0.020 inch) 0.5 mm (0.020 inch)
Compression Ratio 8.6:1 9.5:1 9.5:1
Starter 12 VDC 12 VDC 12 VDC
Oil Capacity Including Filter Approx. 1.5 Qts Approx. 1.7 Qts Approx. 1.7 Qts
Recommended Oil Filter Generac Part # 070185 Generac Part # 070185 Generac Part # 070185
Recommended Air Filter Generac Part # 0C8127 Generac Part # 0C8127 Generac Part # 0C8127
Operating RPM 3,600 3,600 3,600
FUEL CONSUMPTION
Model # Natural Gas* LP Vapor**
1/2 Load Full Load 1/2 Load Full Load
04389, 04758 74 105 0.91/33 1.21/44.1
04556, 04759 114 185 1.34/48.9 2.17/79.0
04390, 04760 148.5 240 1.73/63.2 2.80/102.3
* Natural gas is in cubic feet per hour. **LP is in gallons per hour/cubic feet per hour.
STATOR WINDING RESISTANCE VALUES / ROTOR RESISTANCE
Model 04692 Models 04389 Models 04456 Models 04390
04679, 04758 04759 04760
Power Winding: Across 11 & 22 0.190-0.208 ohms 0.223-0.259 ohms 0.115 ohms 0.08/0.08 ohms
Power Winding: Across 33 & 44 0.190-0.208 ohms 0.223-0.259 ohms 0.115 ohms 0.08/0.08 ohms
Excitation Winding: Across 2 & 6 1.442-1.670 ohms 1.53-1.77 ohms 0.745 ohms 0.705 ohms
Engine Run Winding: Across 55 & 66A 0.104-0.120 ohms 0.100-0.169 ohms 0.109 ohms 0.087 ohms
Battery Charge Winding: Across 66 & 77 0.137-0.158 ohms 0.146-0.169 ohms 0.164 ohms 0.130 ohms
Rotor Resistance 15.42-17-85 ohms 11.88-13.76 ohms 15.9 ohms 19.8 ohms

Page 4
SPECIFICATIONS
LEFT
S
IDE VIE
W
TRAN
S
FER
S
WIT
CH
FR
O
NT VIE
W
(
IF SUPPLIED
)
"D
O
N
O
T LIFT BY THE R
OO
F
"
LIFTIN
G
H
O
LE
S
4-
CO
RNER
S
Ø
30
.2mm
[
Ø
1.19"
]
**ALL DIMEN
S
I
O
N
S
IN
:
MILLIMETERS
[
INCHES
]
76.2mm
[
3.00"
]
PEA
G
RAVE
L
MIN
U
M
UM
716
[2
604
[
23.5"
]
1193
[
47"
]
308
[
12"
]
74
3
[
29.25"
]
207
[
8.14"
]
7
04
[
27.7"
]
622
[
24.5"
]
1232
[
48.5"
]
H
O
ME
S
TANDBY
G
ENERAT
OR
IN
S
TALLATI
O
N DIA
G
RA
M
0
D
3
7
39
MOUNTING DIMENSIONS

Page 5
SPECIFICATIONS
REAR VIEW
RI
G
HT
S
IDE VIE
W
AIR
OU
T
L
AIR INTAKE
G
R
OU
NDIN
G
L
UG
3/
4" NPT F
U
EL INLE
T
G
A
S
PRE
SSU
RE
O
F 11-14
"
WATER COLUMN RE
Q
UIRE
D
**ALL DIMEN
S
I
O
N
S
IN
:
MILLIMETERS
[
INCHES
]
914mm
[
36.0"
]
MINIM
U
M
O
PEN ARE
A
ALL AR
OU
ND
U
NI
T
260
[
10.2"
]
14
9
[
5.9"
]
1172.3
[
46.2"
]
490.7
[
19.3"
]
C
ABLE A
CC
E
SS
H
O
LE
S.
(
REMOVE PLUG FOR ACCESS
)
H
O
ME
S
TANDBY
G
ENERAT
OR
IN
S
TALLATI
O
N DIA
G
RA
M
MOUNTING DIMENSIONS

SPECIFICATIONS
Page 6
MAJOR FEATURES
CONTROL PANEL
BATTERY COMPARTMENT
FUEL REGULATOR
AIR FILTER
EXHAUST
ENCLOSURE
OIL FILTER
DATA DECAL
(BEHIND BATTERY COMPARTMENT)
CONTROL
PA N E L
AIR FILTER
EXHAUST
ENCLOSURE
BATTERY COMPARTMENT
FUEL REGULATOR
OIL FILTER
OIL DIPSTICK
DATA
DECAL
(BEHIND BATTERY COMPARTMENT)
12 kW and 15 kW, V-twin GT-990 Engine
7 kW, Single Cylinder GH-410 Engine

PART TITLE
1.1 Generator Identification
1.2 Prepackaged Installation Basics
1.3 Preparation Before Use
1.4 Testing, Cleaning and Drying
1.5 Engine-Generator Protective Devices
1.6 Operating Instructions
1.7 Automatic Operating Parameters
PART 1
GENERAL
INFORMATION
Air-cooled, Prepackaged
Automatic Standby Generators
Models:
04389, 04758 (6 kW NG, 7 kW LP)
04456, 04759 (12 kW NG, 12 kW LP)
04390, 04760 (13 kW NG, 15 kW LP)
TABLE OF CONTENTS
Page 7

INTRODUCTION
This Diagnostic Repair Manual has been prepared
especially for the purpose of familiarizing service per-
sonnel with the testing, troubleshooting and repair of
air-cooled, prepackaged automatic standby genera-
tors. Every effort has been expended to ensure that
information and instructions in the manual are both
accurate and current. However, Generac reserves the
right to change, alter or otherwise improve the prod-
uct at any time without prior notification.
The manual has been divided into ten PARTS. Each
PART has been divided into SECTIONS. Each SEC-
TION consists of two or more SUBSECTIONS.
It is not our intent to provide detailed disassembly and
reassemble instructions in this manual. It is our intent
to (a) provide the service technician with an under-
standing of how the various assemblies and systems
work, (b) assist the technician in finding the cause of
malfunctions, and (c) effect the expeditious repair of
the equipment.
ITEM NUMBER:
Many home standby generators are manufactured to
the unique specifications of the buyer. The Model
Number identifies the specific generator set and its
unique design specifications.
SERIAL NUMBER:
Used for warranty tracking purposes.
Figure 1. A Typical Data Plate
Item # 0055555
1234567
120/240 AC
125/62.5
15000
Serial
Volts
Watts
1 PH, 60 HZ, RPM 3600
NEUTRAL FLOATING
CLASS F INSULATION
MAX OPERATING AMBIENT
TEMP - 120F/49C
FOR STANDBY SERVICE
MAX LOAD UNBALANCED - 50%
GENERAC POWER SYSTEMS
WAUKESHA, WI
MADE IN U.S.A.
Amps
Page 8
PART 1 GENERAL INFORMATION
SECTION 1.1
GENERATOR IDENTIFICATION