ST-94112N page 3 of 4
ELECTRICAL
A
B
Battery
R
un
5
9
13
10 11 12
14
A
B
6
A
B
7
A
B
A
B
A
B
A
B
A
B
8
1
2
3
4
ON/OFF
Switch
Push/Pull Solenoid
Solenoid Valve
Slave Relay
Start
Pushbutton
Coil
Distributor
Starter
Motor
To B
2 Amp
Fuse
Flyback
Diode
Flyback
Diode
Flyback
Diode
Flyback Diode
To Hold Coil
To Pull-in Coil
ON
1 2 3 4 5 6 7 8
The Figures below show typical customer switch wiring for the ST8.
Switch wiring should be run separately from other wires;
DO NOT
route switch wires with AC power wires since voltages, that may
be induced into the switch wires, may exceed rating and cause
damage to circuits or cause false trips.
Figure 1
shows the wiring for a normally open (N.O.) SWICH-
GAGE
®
connected between terminal B and the negative power input.
A metal jumper is connected between A and B. When the SWICH-
GAGE
®
closes the shutdown/alarm circuit will be initiated.
Figure 2
shows the wiring for a normally closed (N.C.) switch
connected to input terminals A and B. The factory installed
metal link must be removed to use this wiring. When the switch
opens the shutdown/alarm will be initiated.
Figure 3
shows the wiring for a N.O. SWICHGAGE
®
which is the
same as Figure 1 except two wires are run from terminals A and B to
the SWICHGAGE
®
. This Closed Loop™ wiring circuit monitors the
wires as well as the switch. If the circuit is opened due to a loose
connection or broken wire or the SWICHGAGE
®
closes, the shut-
down/alarm circuit will be initiated.
Figure 4
shows the ST8 internal SPDT relay in the “run” or operat-
ing mode.
Typical Wiring
Below is a typical wiring diagram for the ST8 TATTLETALE
®
.
A
B
A
B
A
B
9
N.O.
N.C.
C
10 11
Figure 1: Typical N.O.
Sensor Connection
Figure 2: Typical N.C.
Sensor Connection
Figure 3: Typical N.O.
Closed Loop™ Sensor Connection
Figure 4: Internal Relay
Circuit
NOTE: connect only one shutdown device
to the ST8. Wiring for Push/Pull Solenoid,
Solenoid Valve and Slave Relay shown for
clarity only.
Engine Oil
Pressure
Engine Water
Temperature
Low
Water
Level
Internal Relay
(shown in run
mode)
ST8
Shutdown
Sensor Inputs
Differential
Pressure
No Connection
No Connection
No Connection
No Connection
Sensor Lockout Switches
Remove jumper from
terminals 12 and 13 and
set individual sensor
Lockout Switch for a 25 to
35 second lockout time
delay during startup (see
page 4: Setting Lockout
Switches).
Jumper Wire
(customer supplied)
ST8
Shutdown
Sensor
Inputs
