
Such substitutions would jeopardize the safety and health of inhabitants. The Stainless Steel non-restricted direct vent cap must be furnished by the boiler manufacturer in accordance with AGA/CGA requirements. 47 Outdoor Installation with Add-On Condensing Heat Exchanger Outdoor models are self -venting when installed with the factory-supplied non-restricted direct vent cap and require no additional vent piping. This special vent cap is provided with the boiler in accordance with AGA/CGA requir