Generac QT04524ANSX Engine Protective Devices, High Coolant Temperature Sender, Dc Fuses

Engine Protective Devices

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.

NOTE:

Engine protective switches and sensors are mentioned here for the reader’s convenience. Also refer to the applicable control panel manual for additional automatic engine shutdown infor- mation.

HIGH COOLANT TEMPERATURE SENDER

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.

LOW COOLANT LEVEL SENSOR

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.

LOW OIL PRESSURE SWITCH

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.

OVERCRANK SHUTDOWN

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.

NOTE:

If the fault is not corrected, the overcrank feature will continue to activate.

Approximate Crank Cycle Times

•15 seconds ON

•7 seconds OFF

•7 seconds ON

•7 seconds OFF

•Repeat for 45 seconds

•Approximately 90 seconds total.

OVERSPEED SHUTDOWN

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.

RPM SENSOR LOSS SHUTDOWN

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

DC FUSES

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.

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05/10 B .Rev EngProt003