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An explanation for householders
A cylinder thermostat switches on and off the heat supply
from the boiler to the hot-water cylinder. It works by sensing
the temperature of the water inside the cylinder, switching
on the water heating when the temperature falls below
the thermostat setting, and switching it off once this set
temperature has been reached.
Turning a cylinder thermostat to a higher setting will not
make the water heat up any faster. How quickly the water
heats up depends on the design of the heating system, for
example, the size of the boiler and the heat exchanger inside
the cylinder.
The water heating will not work if a time switch or
programmer has switched it off. And the cylinder thermostat
will not always switch the boiler off, because the boiler
sometimes needs to heat the radiators.
Cylinder thermostats are usually fitted between one quarter
and one third of the way up the cylinder. The cylinder
thermostat will have a temperature scale marked on it, and
it can be adjusted to the chosen temperature, then left
to do its job. The thermostat must be designed to kill off
harmful bacteria in the water. Raising the temperature of the
stored hot water unnecessarily results in wasted energy and
increases the risk of scalding.
Dual cylinder thermostats combine both the controller and
the limit thermostats into one common unit.
If you have a boiler control thermostat, it should always be set
What is a Cylinder Thermostat?
