Expansion Vessel Calculator
Instantly calculate the correct vessel size for your heating system. Based on EN 12828 standard and Henrad radiator specifications.
EN 12828 Formulas
Pre-charge Calculation
Step-by-step Breakdown
How Does Expansion Vessel Sizing Work?
The expansion vessel absorbs the expansion of water as your heating system warms up. Water expands approximately 4% when heated from 10°C to 80°C. Without an expansion vessel, pressure would rise to unacceptable levels. The EN 12828 standard prescribes how to calculate the correct vessel size based on total water volume, system temperatures, and static height of the installation.
Setting the Pre-charge Pressure
The pre-charge pressure of the expansion vessel must be set correctly before the system is filled. The formula is: pre-charge = 0.5 bar + (static height / 10). For a system with 5 meters of height, the pre-charge is 1.0 bar. An incorrect pre-charge leads to pressure loss or excessive pressure rise during heating.
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Radiator Calculator