Generac®Power Systems, Inc. 15

Section 3 - Operation

Guardian Liquid-cooled 25 kW Generator

3. Under no load condition, increase the GAIN pot

as much as possible without causing instability.

4. Apply 1/4, 1/2, 3/4 and full load to the unit.

Decrease the GAIN pot if there is instability at any

load point.

5. Under full load condition, increase the stability

pot until the unit returns to 60 Hertz (or 50 Hertz

in 50 Hertz applications).

6. Reduce load to 3/4, 1/2, 1/4 and no load.

Decrease the stability pot if there is instability at

any load point.

7. Adjust differential pot to make the recovery to

load changes even faster and minimize load

change undershoot and overshoot. If it is set too

high, it may introduce oscillations at some load.

It can be set to zero (full CCW) if a small amount

causes oscillations at some load.

Figure 3.2 — Engine Governor Adjustment

3.5 RETRANSFER AND SHUTDOWN

When utility power source voltage has been restored,

electrical loads may be transferred back to that

source and the generator can be shut down as fol-

lows:

• Verify that utility power supply voltage to the trans-

fer switch has been positively turned Off, using

whatever means provided (such as utility main line

circuit breaker).

• Set the generator’s main circuit breaker to its Off

or Open position.

• Let the generator engine run at no-load for a few

minutes, to stabilize internal unit temperatures.

• On the generator console, set the Auto/Off/ Manual

switch to Off. Wait for engine to come to a complete

stop.

• For transfer to utility position, refer to the Owner’s

Manual of the particular transfer switch.

• Turn on the utility power supply to the transfer

switch, using whatever means provided (such as a

utility main line circuit breaker). The utility power

source now powers the loads.

3.6 AUTOMATIC OPERATION

To set the system for fully automatic operation, pro-

ceed 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.

3.7 WEEKLY EXERCISE CYCLE

The engine control board will start and run the gen-

erator once every seven days for approximately 12

minutes. If utility should fail during this exercise

period, the engine control board will transfer the load

to the generator output and continue to run until util-

ity returns.

On the day, and at the time of day chosen for the gen-

erator to exercise, set the weekly exercise cycle as fol-

lows:

1. Place the AUTO/OFF/MANUAL switch in the auto

position (Figure 3.3).

2. Press and hold the “Set Exercise” switch for five

seconds, then release.

Figure 3.3 - “Set Exercise Time” Switch

FOR STAND-BY SERV
TRANSFER SWITCH I
N
ATTENTION: POUR L'
I
CE A UN CO
M
CA
N
RI
S
K
O
F ELE
C
TRI
C
A
L
PARTS INSIDE.
R
THISEMERGEN
N
A
U
T
O
MATI
CA
IN
JU
RY REM
O
L
O
W
COO
LANT LEVE
L
HI
COO
LANT TEMPERAT
U
R
E
FLA
S
HIN
G
G
REEN LED = N
O
U
TILITY
S
EN
SE
5
FLA
S
HIN
G
RED LED'
S
= EXER
C
I
S
ER N
O
T
S
E
T
(
IN AUTO MODE ONLY
)
SOLID GREEN LED = SYSTEM READY, UTILITY POWER O
N
(
SEE OWNER'S MANUAL FOR COMPLETE DETAILS
)
LED INDI
C
AT
O
R
S:
RED LED'
S
= INDIVID
U
AL FA
U
L
T
O
VER
C
RAN
K
S
Y
S
TEM READ
Y
L
O
W BATTER
Y
L
O
W
O
IL PRE
SSU
R
E
O
VER
S
PEE
D
O
F
F
MAN
U
A
L
A
U
T
O
START
,
RUN THROUGH THE EXERCISE
C
Y
C
LE AND
S
H
U
TD
O
WN
.
TIME
S
E
T
EXER
C
I
SE
T
O
A
U
T
O
P
OS
ITI
O
N
.
S
WIT
C
H IN "
O
N" P
OS
ITI
O
N F
OR
1
)
PLACE AUTO/OFF/MANUAL SWITC
H
2
)
HOLD "SET EXERCISE TIME
"
T
O
S
ET EXER
C
I
S
ER TIM
E
1
0
S
E
CO
ND
S
. THEN THE
U
NIT WILL
THE EXER
C
I
S
ER I
S
N
O
W
S
ET. ALL
FIVE RED LED'
S
WILL FLA
S
H F
OR
THREE
S
E
CO
ND
S
AND RELEA
S
E
.
ON
0
F
0653
O
F
F