The Vokera non-return valve is located underneath the appliance and gives the user the ability to restrict the flow of water and gas into the central heating system. These also allow you to stop the flow completely in case of a leak or emergency.
It fits near the plate heat exchanger
Technical specification
Waist Sizeab64ch94gsTypeNon-Return ValveToilet Cistern CapacityFTW--Supplier Part Number2908Brand NameVokera