855424 6 Mercury FITTING

Introduction
Do not perform any procedure in this Special Instruction until you read this information and you understand this information.This Special Instruction describes the retrofitting from jacket water heaters that circulate the jacket water by the convection of heat to a jacket water heater that utilizes a pump in order to circulate the jacket water.Theory of Operation
Illustration 1 g01624957
Schematic of the coolant flow (1) Pump (2) Heater (3) Control boxThe new jacket water heater is mounted to the rail on the left side of the engine. The new heater consists of a pump, a heater, and a control box. The heater contains three heating elements and a thermostat.The heater is activated and deactivated by the controller on the generator set. When the controller for the generator set activates the contactor for the space heater, electrical power is supplied to the space heater (if equipped), to the pump, and to the thermostat.The pump continuously draws coolant from the rear of the engine block into the heater. The contacts of the thermostat will close when the temperature of the coolant is below the set point. The closed contacts of the thermostat complete an electrical circuit that supplies power to the coil of the contactor for the water heater. The contactor for the water heater supplies electrical power to the heating elements. The heating elements heat the coolant and the coolant is returned to the engine block by the pump.When the engine is running, the controller for the generator set deactivates the contactor for the space heater. This disables the pump, the thermostat, and the heating elements.Electrical RequirementsThe customer must provide a source of three-phase 480 VAC at 60 Hz. This electrical source must be protected by a 20 amp circuit breaker. A transformer is provided inside the control box which provides single-phase 240 VAC at 60 Hz to the pump.Parts Lists
Order the jacket water heater that is appropriate for the application. Refer to Table 1.
Table 1
Jacket Water Heater Gp    
60 Hz Generator Sets    
325-6250 Jacket Water Heater Gp    For single-phase 220 VAC and 240 VAC heaters, refer to Special Instruction, REHS1658-01, "Replacing the Convection Jacket Water Heaters with a Recirculating Jacket Water Heater on 3500 Engines".Order the additional parts that are appropriate for your engine. Refer to Tables 2 and 3. Look up the pricing arrangement for the engine and for the frame in Table 3. Find the required parts from Table 2.
Table 2
List of Required Parts for Installation    
Part Number     Description     Feature Code
JWHWP    
37 38     39     40     41     42     43     44     45     46     47    
325-6250     Heater Gp     1     1     1     1     1     1     1     1     1     1     1    
307-8457     Mounting Gp     0     1     0     1     0     0     1     0     1     0     0    
307-8458     Mounting Gp     1     0     0     0     1     0     0     1     0     1     1    
307-8459     Mounting Gp     0     0     1     0     0     1     0     0     0     0     0    
328-3418     Wiring Gp     0     0     0     0     1     0     0     0     1     0     0    
328-3423     Wiring Gp     1     1     0     0     0     0     0     0     0     0     0    
328-3426     Wiring Gp     0     0     0     0     0     0     0     0     0     0     1    
328-3429     Wiring Gp     0     0     1     0     0     0     0     0     0     0     0    
328-3432     Wiring Gp     0     0     0     1     0     0     0     0     0     1     0    
313-5252     Connection Gp     1     1     1     1     1     1     1     1     1     1     1    
Table 3