As a minimum,
regulating a hot water heating circuit is carried out by manually setting the
adjustable aquastat of the boiler.
Indentify on the wall-mounted boiler control panel below, the setting button for the adjustable aquastat (for heating).
Aquastat control switch
If the user only has the boiler aquastat to control his heating, he must start (and end) his heating season by positioning the aquastat on minimum then increasing the set point by small amounts depending on the heating felt.
At the beginning of the heating season, the power supplied will be excessive (water temperature too high).
The eventual fitting of thermostats on the radiators may not be enough to obtain a correct comfort level.
Either he must shorten his heating season (to the detriment of his comfort) or he over-consumes, because the over-heating periods at the beginning and end of season will be substantial.
This type of operating is only suitable for wall-mounted gas boilers. It is not recommended for standards fuel boilers because they should operate at high water temperatures as much as possible. It is “acceptable” for wall-mounted gas boilers with atmospheric burners because the condensation risk of steam produced during start up is minimal.
Obviously, on a system where the only control is a manual aquastat on the boiler, we would recommend the fitting of an ambient thermostat. In general it will lead to more comfort and energy saving.
However, its fitting could lead to an increase in energy consumption if the user manually maintains a very low level of heating. We must remember that a reasonable level of heating is necessary for building conservation (to avoid problems of condensation).