8.10
Change-over the diesel fuel - general
When you change from heavy fuel oil (HFO) to marine diesel oil (MDO) or back, you must keep
the thermal stresses of the related fuel components as low as possible. Thermal stress occurs
because of the large temperature changes. Too fast change of the temperature can cause damage
to the fuel pump plungers and can cause leakages in the fuel pipes.
During the change-over procedure the temperature of the fuel must not change more than 2°C
each minute. This prevents damage to the system, specially when you do the procedure frequently.
The small change rate is also because of the large difference of viscosity between HFO and MDO/
MGO.
You can do a change-over of the fuel only when the engine is running. While the engine has
stopped, there is no fuel flow through the fuel rail. In this situation a change-over is not possible.
8.10.1
Automatic fuel change-over
WinGD recommends the installation and use of an automatic fuel change-over system to prevent
problems during the change-over procedure.
•
This system decreases the thermal load of the related fuel components (for example fuel
pump plungers).
•
The safety functions decrease the risk of damage because of thermal loads.
•
You can do the change-over procedure at a load of up to 100% CMCR.
•
The time period for automatic change-over is less than that of a manual change-over.
8.10.2
Manual fuel change-over
When you do a manual change-over of the fuel, you must make sure that the change-over is safe.
Refer to the related procedures.
Make sure that during the procedures HFO never can flow into the MDO tank and pipe system.
NOTE:
WinGD recommends to do a manual change-over only, if an automatic change-over
system is not installed or if the automatic change-over system is unserviceable.
8.10.3
Recommended viscosity at the inlet of the fuel pumps
For the temperature necessary to make sure that the fuel upstream of the inlet to the fuel pumps
is at the correct viscosity, refer to the Viscosity / Temperature Diagram in the related specification,
refer to section
12.1 General for operating media
. The viscosity for MDO must not be less than 2
cSt.
A viscosimeter measures the viscosity and thus controls the temperature of the fuel.
Make sure that you monitor the viscosity and the temperature of the fuel.
X72-B
AA00-0000-00AAA-130D-A
Operation Manual
Change-over the diesel fuel - general
Winterthur Gas & Diesel Ltd.
- 332 -
Issue 003 2021-12
