A Worcester Bosch spare pressure relief valve is suitable for use with Camray 5, 240, Camray, CDi Series, Danesmoor, Heatslave, Camray Quartet, 9.24 Electronic, Highflow, Economy Combi, Camray Combi, 280, 350, 230 and Greenstar appliances. The pressure relief valve helps to control pressure in a closed system by proportionally opening to relieve excess pressure, preventing catastrophic malfunction.