ÖNORM EN 1490

This European Standard specifies, dimensions, materials and performance requirements (including methods of test) for combined temperature and pressure relief valves, of nominal sizes from DN 15 to DN 40, having working pressures1) from 0,1 MPa (l bar) to 1,0 MPa (10 bar). Combined temperature and pressure relief valves are intended for fitting to storage water heaters, having a maximum distribution temperature of 95 C, for all energy sources. Combined temperature and pressure relief valves control and limit the temperature and pressure of the water contained in a hot water heater to the valves rating pressure and a temperature not exceeding 100 ºC and will prevent water to steam formation when other temperature controls fail. They are not intended to act as an expansion valve under normal conditions and does not control cold water flow. Alone it does not constitute the control functions for a water heater. NOTE : The use of the device specified in this Standard does not override the need to use controls (e.g. thermostats and cut-outs) which act directly on the power sources of water heaters.