SHUTOFF AND ALARM SYSTEMS
SYSTEMS OPERATION
WATER TEMPERATURE AND OIL PRESSURE SHUTOFF SYSTEM
(WITH TIME DELAY RELAY)
WIRING DIAGRAM
(Fuel Shutoff Solenoid Energized to Shutoff)
1. Time delay relay. 2 Oil pressure switch 3. Water temperature switch. 4. Switch (N.O.) 5 Circuit breaker.
6. Shutdown relay. 7. Battery. a Diode assembly. 9. Shutoff solenoid. 10 Starter motor.
When the engine starts, engine oil pressure will close the
N.O. switch and open the N.C. switch in oil pressure
switch (2). This completes the circuit to time delay relay
(1). N.O. switch (4) in the time delay relay now closes
and completes the circuit between shutdown relay (6)
and terminal TD-7 of the time delay relay.
If the engine coolant temperature goes above the setting
of water temperature switch (3), the N.O. contacts will
close. This lets current flow through water temperature
switch (3) and through switch (4) to activate shutdown
relay (6) which in turn activates fuel shutoff solenoid (9).
When the engine stops, engine oil pressure will become
less than the setting of the oil pressure switch. The N.O.
switch will open and stop the flow of current to the time
delay relay. This will start the time delay relay timer. After
70 seconds, switch (4) will open to stop current flow
through shutdown relay (6). Now, fuel shutoff solenoid
(9) will no longer be activated.
If engine oil pressure gets less than the setting of the oil
pressure switch, the N.C. switch will close. This will let
current flow through switch (4) to activate shutdown relay
(6) which in turn activates fuel shutoff solenoid (9). The
N.O. switch will open and start the time delay relay timer.
After 70 seconds, switch (4) will open to stop current flow
through shutdown relay (6). Now, fuel shutoff solenoid
(9) will no longer be activated.
NOTICE
To help prevent damage to the engine, find and
correct the problem that caused the engine to
shutdown before the engine is started again.
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