All Zilmet expansion vessels are tested and pre-filled at the factory. The precharge value can be optimized according to need. Normally it is advisable to set the following precharge values, depending on the type of application:
- Heating circuit: it is advisable to set the precharge value at the same pressure value as the system. The measurement must be carried out with the system stopped and unloaded.
- Sanitary circuit: it is advisable to set the precharge value to the value of the average inlet pressure of the circuit (aqueduct pressure) or to the calibration pressure of the pressure reducer, if present.
- Pressurization systems: the precharge value must be approximately 0.2 bar lower than the pump start pressure.
In any case, the pre-charge value must never exceed the 50% of the maximum operating pressure of the vessel and any adjustment must be carried out by qualified and authorized personnel.
