SEAL AS-BUFFER 1672725 - Caterpillar

The 3600 and G3600 Engines can use a jacket water heater, a lube oil heater, or a combined heating system for jacket water and for lube oil. The heaters provide warm coolant and/or engine oil for quicker start-ups.Note: In 3600 Marine Engines for harbor tugs, a heating system for the lube oil is required. This requirement can be met with a lube oil heater or with a combined heater.The operation of the lube oil heater and the jacket water heater are described in this section. Each heating system has one control box for a single pump and for a single heating tank.Note: The combined heating system has one control box for two pumps and for two heating tanks.The pump's motor and the heater are wired to the control panel. Wiring to a power source must be completed in order to finish the installation at the site.If the heating system is not installed at the factory, installation must be completed by the customer. Fluid supply lines and return lines must be installed between the engine and the heater. Refer to Systems Operation Section, "Installation and System Start-Up".This manual is written in order to support heaters which are released for current production. This manual also contains information that will be helpful in understanding and identifying parts that are used in many earlier custom heating systems.Circulation of Coolant
Illustration 1 g00883536
Schematic of the coolant flowUpon energizing the heating system, coolant is drawn from a low point in the engine's cooling system. The coolant is circulated by a centrifugal pump through the heating tank. The coolant exits the tank through a switch that senses the fluid flow (flow switch). The heated coolant is pumped to the top of the engine. The coolant flows downward through the engine for recirculation.During engine operation, a solenoid valve at the heater's outlet limits the coolant's backflow. The solenoid also limits the backflow when the heating system is shut down.Circulation of Lube Oil
Illustration 2 g00883468
Schematic of circulation of lube oilUpon energizing the system, engine oil is drawn from the engine oil sump. The engine oil is circulated by a gear pump through the heating tank. The heated engine oil exits the tank through a switch that senses the fluid flow (flow switch). The engine oil is routed back to the engine oil sump for recirculation.A check valve at the heater's outlet limits the backflow when the heating system is shut down.Electrical System Operation
Illustration 3 g01365810
Operational schematic of the electrical system (1) Customer supplied circuit breaker (2) Fuse (3) Transformer (4) Control relay (5) Control box's on/off switch (6) On/off indicator (7) Solenoid (8) Time delay relay (9) Coil for the pump motor's contactor (10) Pump motor's contactor (11) Pump motor's protective switch (12) Pump motor (13) Flow switch (14) Pump motor's protective switch's auxiliary contacts (15) Thermostat (16) Coil for the heating element's contactor (17) Heating element's contactor (18) Heating elementNote: Except for the few differences that are noted, the jacket water heater and the lube oil heater operate in the