Immersion heating

Note on Legionella:

The hot water cylinder is a prime place for the legionella bacteria to live and multiply. Here is some basic information on the legionella bacteria.


a). The formation of this bacteria is still quite rare, but, it is likely to form in water with a temperature below 60° C, it will not really live very long at this temperature and will die if the temperature is increased. A Waltham Forest Plumber is highly aware of the dangers of legionella.


b). Legionella survives at a water temperature that sits between 20°C-40° C and is usually spread in a vapour or mist formation. Provided the temperature of the water is regulated there will not be a problem and the Legionella will not form.


Immersion heater:

The name immersion actually refers to the electrically operated element that sits in the water tank and heats the water. If you like it is very similar in operation to the kettle, but on a much bigger scale. Waltham Forest Plumbers can fit immersion heaters. The heating element sits in the tank and is controlled by a thermostat that will send current through the element if the temperature of the static water in the tank falls below 60°C. This acts as protection for the homeowner, preventing them from being burned (the water temperature is maintained at this level).


Basic Operation:

The way this system works is that the tank with the immersion heater inside is fed by a cold water supply which enters at the bottom. The immersion heater or heaters (more than one can supply the system), starts to heat the water. The hot water is then be drawn from the top of the tank. A cylinder that is unvented requires a high limit cut-out thermostat to be fitted at (90°C) so that it does not boil. It is at this lower temperature that the legionella can form. So the system must be balanced in temperature.