Wartsila ?31DF Series, Product Manual, Page: 22 / 216

2.3 Low load operation
2.3.1 Normal Low load operation - Normal load acceptance
In order to avoid fouling of the engine, recommended limits to the low load operation are given.
Low load operation is all loads below 20% load. Cumulative low load operation should not
exceed the recommended values given in the chart and table. The time is reset after a cleaning
run at minimum 70% load for a minimum of 1 hour.
Black line (diesel mode) limit is valid in diesel mode when intention is to continue in diesel
mode. In case the intention is to transfer to gas mode and continue operating in gas mode
then blue line (gas mode limit) is valid also for diesel mode.
The loading rates according to Normal low load load operations, chapter load performance
are allowed with these low load operation limits.
If recommended time limits are exceeded then engine shall not be loaded faster than the
nominal loading curve in the chapter loading performance.
Absolute idling time 10 minutes if the engine is to be stopped, 5 hours in gas mode or 10 hours
in diesel mode if engine is loaded afterwards.
2-8 DBAE248994
Wärtsilä 31DF Product Guide 2. Operating Ranges