Tundish discharge fitting, for use with DN40 and DN50 Caleffi RPZ Valves. The Tundish collects the discharged contents of the valve if the supply pressure reduces by more than 0.3 bar whilst there is no flow. There may also be a discharge from the RPZ if there is a fault within the valve. The Tundish provides a type AA air gap to satisfy the requirements of the Water Regulations.