How do Immersion Heaters work?
Immersion heaters work exactly the same as an electric kettle. There is at least one element inside that heats the water, controlled by a thermostat to make sure the water doesn’t get too hot or boil away. Here’s a good link: http://home.howstuffworks.com/water-heater1.htm The safety precautions concern the wiring and thermostat, but this is not something the average householder worries about.
