This paper discusses optimal control strategies for switching between different burner modes in a novel compact marine boiler design. The ideal behaviour is defined in a performance index the minimisation of which defines an ideal trade-off between deviations in boiler pressure and water level from their respective setpoints and the cost of burner switches and variation of continuous input flows. Direct minimisation was found computational infeasible and two different suboptimal strategies have beenconsidered. The first one is based on the Mixed Logical Dynamical framework. Thesecond approach is based on a generalisation of hysteresis control. The strategies are verified on a simulation model of the compact marine boiler for control of low/high burner load switches.