Engine protective devices, Low oil pressure switch, High coolant temperature switch – Generac Power Systems 004475-1 User Manual
Page 7: Low coolant level switch, Figure 1.3 - engine protective devices, Figure 1.4 - low oil pressure switch, Figure 1.5- high coolant temperature switch, Figure 1.2 - main circuit breaker
Generac
®
Power Systems, Inc.
5
Gaseous fuels such as natural and LP (propane)
gas are highly explosive. Even the slightest spark
can ignite such fuels and cause an explosion. No
leakage of fuel is permitted. Natural gas, which is
lighter than air, tends to collect in high areas. LP
gas is heavier than air and tends to settle in low
areas.
ENGINE PROTECTIVE DEVICES
The engine has several safety switches which cause the
engine to automatically shut down under the following
conditions: low oil pressure, high coolant temperature,
engine overspeed, low coolant level or overcrank (Figure
1.3).
Figure 1.3 - Engine Protective Devices
LOW OIL PRESSURE SWITCH
This switch is normally-closed (N.C.) but is held open
by engine oil pressure during engine running. Should
operating oil pressure drop below about 8-10 psi (55-68
kPa), the switch contacts close and the engine shuts
down automatically (Figure 1.4).
Figure 1.4 - Low Oil Pressure Switch
HIGH COOLANT TEMPERATURE SWITCH
Normally open (N.O.) thermostatic switch has sensing
tip which is immersed in captive coolant. Should
coolant temperature exceed about 230°F (110°C), the
switch contacts close, which causes the engine to shut
down automatically (Figure 1.5).
Figure 1.5- High Coolant Temperature Switch
LOW COOLANT LEVEL SWITCH
Should engine coolant level drop below the level of the
high coolant temperature switch, it is possible for the
engine to overheat without automatic shutdown. To pre-
vent such overheating without automatic shut down, the
engine has a low coolant level sensor. If the engine
coolant drops too low, the engine automatically shuts
down (Figure 1.6).
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Section 1 - General Information
Guardian Liquid-cooled 15 kW, 20 kW and 25 kW Generators
Model
Rating
Phase
Actual Current
C/B Rating*
% over rating
Circuit Breaker
004188
15,000
1
62.5
70
112%
70A BQ2
004189
15,000
1
62.5
70
112%
70A BQ2
004370
20,000
1
83.3
90
108%
90A BQ2
004371
20,000
1
83.3
90
108%
90A BQ2
004474
25,000
1
104.2
125
120%
125A BQ2
004475
25,000
1
104.2
125
120%
125A BQ2
* Amp Rating of C/B structured under model.
Figure 1.2 - Main Circuit Breaker