Installation using a 5" Diameter Metal Flue Box. Important: The spigot restrictor marked B� must be fitted See Fig. 4 When the metal flue box is to be built-in as a false chimneybreast using timber studwork with plasterboard facing, the metal flue box should be enveloped with insulation material such as rockwool or similar to prevent a build-up of heat within the structure. Either an air gap of 75mm should be maintained between any combustible materials and any part of the metal flue box or a minimum of 25rmm of insulation material between the metal flue box and the combustible material. It is important that both the back panel and the appliance are sealed to the metal flue box to prevent any leakage of flue products or reduction in the flue draught.
