Vaillant 178985 pressure relief valve

This Vaillant pressure relief valve is a replacement part suitable for use with Guernsey/Jersey only (condensing), ecoTEC VU (condensing), ecoTEC VUI (condensing), ecoTEC VUW (condensing), VWL (heat pump) and Home (condensing) boilers. The pressure relief valve helps to control pressure in a closed system by proportionally opening to relieve excess pressure, preventing catastrophic malfunction.