PUMP AS-FUEL TRANSFER 7C9748 - Caterpillar

Introduction
When the words "use again" are in the description, the specification given can be used to determine if a part can be used again. If the part is equal to or within the specification given, use the part again.When the word "permissible" is in the description, the specification given is the "maximum or minimum" tolerance permitted before adjustment, repair and/or new parts are needed.A comparison can be made between the measurements of a worn part and the specifications of a new part to find the amount of wear. A part that is worn can be safe to use if an estimate of the remainder of its service life is good. If a short service life is expected, replace the part.Reference: See 3208 Industrial And Marine Engine Attachments, SENR7090, for Specifications. For Specifications with illustrations, make reference to Specifications For 3208 Industrial And Marine Engine Attachments, SENR7090. If the Specifications in SENR7090 are not the same as in the Systems Operation and Testing & Adjusting, look at the printing date on the front cover of each book. Use the Specifications given in the book with the latest date.Electrical System
Contactor Switch For Water Temperature
Water Temperature Contactor SwitchThe contactor switch for water temperature is installed in the front cover for the engine. No adjustment to the temperature range of the contactor can be made. The element feels the temperature of the coolant and then operates the micro switch in the contactor when the coolant temperature is too high. The element must be in contact with the coolant to operate correctly. If the cause for the engine being too hot is because of low coolant level or no coolant, the contactor switch will not operate.The contactor switch is connected to the fuel shutoff solenoid to stop the engine. The switch can also be connected to an alarm system. When the temperature of the coolant lowers to the operating range, the contactor switch opens automatically.Pressure Switch
Pressure SwitchThese type pressure switches are used for several purposes and are available with different specifications. They are used in the oil system and in the fuel system. One use of the switch is to open the circuit between the battery and the fuel shutoff solenoid after the oil pressure is below the pressure specifications of the switch. It also closes when the engine starts.Another use of the switch is to close and activate the battery charging circuit when the pressure is above the pressure specification of the switch. It also disconnects the circuit when the engine is stopped.Some switches of this type have three terminal connections. They are used to do two operations with one switch. They open one circuit and close another with a single switch.Electrical Indicators And Sending Units
The electrical indicators and sending units are to operate in electrical balance. Because of this, the voltage and resistance ratings are important to get the correct indications on the indicators. See Attachment Specifications to determine which indicators and sending units can be used with each other.Sending Unit