CONSTANT PRESSURE AND VARIABLE LEVEL OPERATION Self-pressurised closed expansion vessels, without diaphragm, for superheated water. Externally painted rustproof; to be pressurised with air or nitrogen. Suitable for containing water expansion and maintaining a constant pressure during operation of the system by means of automatic gas venting and filling. Max. permissible pressure 5 bar Max. permissible temperature 120°C  CE certified according to European Dir. 2014/68/EU-PED the expanders are subject to the Declaration of Commissioning (D.M. 329 of 01/12/2004).