Changeover of supply fuel from HFO to DO procedure when ME is operating

To protect the high-pressure fuel equipment from failure, the fuel changeover must be performed manually as follows:
a)    It is necessary to switch off the steam supply to the fuel oil preheater, return fuel and steam tracing pipes.
b)   Reduce engine load to 75% of rated load.

CACAUTION: The temperature of the HFO must not fall below 75ºC.

c)    Replace with diesel fuel when the temperature of the HFO fuel in the heater drops to about 25ºC above the fuel temperature in the diesel tank during the day.
d)   Open the diesel fuel transfer valve. Turn the fuel supply three-way diverter valve to drain fuel from the DO's daily service tank.
e)    Close the fuel transfer system valve.

DiDiesel fuel is now supplied to the main and auxiliary engines.
NOTE: if the fuel temperature in the heater drops very quickly, the fuel temperature drop must be mitigated by heating the fuel with steam.

 Changeover of supply fuel from HFO to DO while ME is operating