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* It is essential to be able to access the various components of your hydraulic
installation during the useful life of your equipment in order to be able to carry out
regular maintenance and intervene or replace components that are necessary over
time.
8.1 Calculation for the minimum volume of the buffer tank
Calculation for the minimum volume of the buffer tank according to the European
standard EN 303-5: 2012 apply the following formula,
VSP = 15 x TB x QN x (1-0,3 x QH/Q
min
)
Where:
VSP = minimum volume buffer tank (l)
TB = combustion time (h)
QN = rated power (kW)
QH = needed for installation (kW)
Q
min
= minimum boiler output (kW)
Example of calculation of the buffer tank:
Combustion Duration: 2 hours (the time required for combustion of the fuel charge)
Nominal boiler power: 32 kW
Minimum boiler power: 32 kW
Thermal load of the building: 25 kW
Minimum volume required = 15 x 2 x 32 x (1-0,3 x 25/32) ≈ 735 l
8.2 Method of calculating the volume expansion vessel
The volume of an enclosed membrane expansion vessel (diaphragm) for a heating
installation is calculated using the following formula,
Where:
V = volume of the vessel (l);
e = coefficient of expansion of the water. Calculated based on the difference between
the maximum temperature of the water in the installation and the maximum cold