This European Standard specifies, dimensions, materials and performance requirements (including methods of test) for expansion groups, of nominal sizes from DN 15 to DN 40, having working pressures 1) from 0,1 MPa (l bar) to 1,0 MPa (10 bar).
Expansion groups are intended for fitting to the cold water supply of storage water heaters, having a maximum distribution temperature of 95°C, for all energy sources.
Expansion groups limit pressure, in the water heater to which they are fitted, that is produced by thermal expansion of the water.
Expansion groups do not control temperature and alone do not constitute the protection required for storage water heaters.
NOTE : The use of the device specified in this Standard does not override the need to use controls (eg thermostats and thermal cut-outs) which act directly on the power sources of water heaters.