How Do Immersion Heaters Work?

We’re heading into what the newspapers are billing to be this year’s “big freeze”. It would be hard to get out of bed without the invigorating prospect of a hot shower. But how is our water heated? How do immersion heaters work?

Here in the UK, the majority of home water heating is done by immersion heaters mounted in hot water cylinders. Immersion heaters comprise a metal tube containing a temperature sensor. Along with this is an insulated electric resistance heater which, in domestic situations, is usually rated at 3kw.

Unlike a gas heated water tank, which has burners below it, immersion heaters heat water directly from inside the tank. A strong electric current is passed through the element which heats the water around it. It works in a similar manner, although on a larger scale, to the average kitchen kettle. The thermostat serves to monitor the temperature of water in the tank. If it drops below a certain point, works to bring it back up to the required level.

In terms of how the heated water is delivered, cold water is fed into the tank at the bottom. Upon heating from the immersion element, the water rises to the top as part of a convection current.

The influx of cold water gives the heated water at the top of the tank the pressure needed to leave the cylinder when it is required.

The immersion heater is wired into the mains electrical supply via an isolating switch. Although considered to be more expensive than a natural gas heater, there’s the advantage of not requiring the same level of ventilation. Additionally, costs can be kept down if a timer is attached to the tank. This means water can be heated up at the most economical time of the day and kept warm via tank insulation.

Options Skills offer training in how to fit and maintain immersion heaters as part of a number of our plumbing courses.

Find out more by calling FREE now on 0808 301 496 or filling in the form on the right.