The output of an immersion type electric boiler is controlled by __________ one or more elements as required.

The output of an immersion type electric boiler is controlled by turning the power on or off one or more elements as required. This method allows for precise temperature control and management of the heat output produced by the heating elements submerged in the water. By switching the power on, the elements heat up, and when turned off, they cease to produce heat, allowing the water temperature to stabilize or drop as needed.

This approach is fundamental in controlling the efficiency and safety of the boiler operation, as it allows operators to respond quickly to changes in demand for hot water or steam generation. It is critical to ensure that the heating elements only operate when needed, helping to conserve energy and extending the lifespan of the equipment. The controlling mechanism is often automated through thermostats or control systems that monitor the water temperature and make adjustments as necessary.

Other options provided do not pertain to the operational control of an immersion type electric boiler in the context of electrical heating. For instance, the idea of controlling the basket level relates more to physical placement than electrical output, while immersing or short-circuiting would entail risks and does not apply to the intended function of heating elements within the boiler.