Question. What expansion vessels must be EC marked ?

Answer. According to the Pressure Equipment Directive PED 2014/68/EU the expansion vessels of which product between the maximum working pressure and the volume is higher than 50 bar x liter, must be EC marked. According to the Pressure Equipment Directive PED 2014/68/EU the expansion vessels, of which product between the maximum working pressure and the volume is lower than or equals 50 bar x liter, can not be EC marked: the expansion vessels, that can not be EC marked, must be designed and manufactured in accordance with the sound engineering practice.

Question. What design methods are used to design the expansion vessels manufactured by Zilmet S.p.A. ?

Answer. According to the Pressure Equipment Directive PED 2014/68/EU, for the expansion vessels, of which product between the maximum working pressure and the volume is lower than 6000 bar x liter, the design method is the experimental method: no calculations are performed for the above expansion vessels. For the expansion vessels of which product between the maximum working pressure and the volume equals or is higher than 6000 bar x liter, the design methods are the calculation method and the  experimental method.

Question. What moduls are used to get the EC mark certification for the expansion vessels and the heat exchangers manufactured by Zilmet S.p.A. ?

Answer. The moduls used to get EC mark certification for the expansion vessels and the heat exchangers manufactured by Zilmet S.p.A. are the following: modul D1 for the pressure equipments in category I and II of the above Directive and moduls B+D for pressure equipments in category III and IV of the above Directive.

Question. How can I install, service and mantain the expansion vessels and the heat exchangers manufactured by Zilmet S.p.A. ?

Answer. With reference to the installation, servicing and maintenance of expansion vessels and heat exchangers manufactured by Zilmet S.p.A., please refer to the instruction manuals available in the restricted area of our web site.

Question. Is it possible to install  an expansion vessel with the connection in upward direction ?

Answer. The installation of the expansion vessel with the connection in upward direction is possible. Nevertheless conditions being equal, the installation of the expansion vessel with the connection in upward direction ( in comparison with the installation of the expansion vessel with the connection in downward direction) makes the draining of water stored in the expansion vessel slower: with reference to the installation, servicing and maintenance of the expansion vessels, please refer to the instruction manuals available in the restricted area of our web site.

Question. How can I size expansion vessels and heat exchangers ?

Answer. With reference to the sizing of expansion vessels and heat exchangers, please refer to the sizing programs available in our web site.

Question. Is it possible to install the expansion vessels, that are suitable for potable water applications according to Zilmet web site and catalogues, on central heating systems ?

Answer. Yes, it is: the expansion vessels suitable for potable water applications can be installed on central heating systems.

Question. Is it possible to install the expansion vessels, that are suitable for central heating systems or for solar systems according to Zilmet web site and catalogues, on systems for the production of potable/ sanitary water ?

Answer. No, it is not: the expansion vessels suitable for central heating systems or for solar systems can not be installed on systems for the production of potable/ sanitary water.

Question. What is the maximum heat exchange power of an heat exchanger ?

Answer. The heat exchange power of an heat exchanger depends on the number of plates and on the working temperatures.

Question. What is the maximum concentration of glycol to be charged to the heating circuit or solar as not to damage the membrane of the expansion vessel?

Answer. For standard applications it is not allowed to use a concentration higher than 50%.