Generac QT04524ANSX User Manual

ENGINE PROTECTIVE DEVICES

The Stationary Emergency Generator may be required to operate 

for long periods of time without an operator on hand to monitor 

such engine conditions as coolant temperature, oil pressure or 

rpm. For that reason, the engine has several devices designed to 

protect it against potentially damaging conditions by automatically 

shutting down the unit when the oil pressure is too low, the coolant 

temperature is too high, the coolant level is too low, or the engine 

is running too fast.

An analog coolant temperture sender, located in the engine's 

cooling system will cause an engine shutdown if the temperature 

should exceed approximately 125° C (257° F). The generator will 

automatically restart once the temperature has returned to a safe 

operating level.

To prevent overheating, the engine has a low coolant level sensor. 

If the level of engine coolant drops below the level of the low cool-

ant level sensor, the engine automatically shuts down.

This switch has normally closed contacts that are held open by 

engine oil pressure during cranking and operating. Should oil pres-

sure drop below the 8 psi range, switch contacts close, and the 

engine shuts down. The unit should not be restarted until oil is 

added, and the AUTO/OFF/MANUAL switch must be turned to OFF 

and then back to AUTO.

After a prespecified duration of cranking, this function ends the 

cranking if the engine has failed to start. The overcrank message 

will turn ON. Turn OFF the AUTO/OFF/MANUAL switch, then turn 

switch back to AUTO to reset the generator control board.

15 seconds ON

• 

7 seconds OFF

• 

7 seconds ON

• 

7 seconds OFF

• 

Repeat for 45 seconds

• 

Approximately 90 seconds total.

• 

A speed circuit controls engine cranking, start-up, operation and 

shutdown. Engine speed signals are delivered to the circuit board 

whenever the unit is running. Should the engine overspeed above 

a safe, preset value, the circuit board initiates an automatic engine 

shutdown. Contact the nearest Authorized Dealer if this failure 

occurs.

If the speed signal to the control panel is lost, engine shutdown 

will occur.

A fuse (7.5 amp) is located on the control panel. It protects the 

panel components from damaging overload. Always remove this 

fuse before commencing work on the generator. The unit will not 

start or crank if the fuse is blown.
A fuse (25 amp) is located in the engine wire harness adjacent 

to the DC alternator. It is used to prevent circuit failure due to DC 

alternator falure. It will also protect the system in the event of a 

wiring short-dircuit. If this fuse is blown, the generator will not 

operate. Replace these fuses with the same size, type, and rating.

EngProt003  R

ev.

 B  05/10

Engine Protective Devices