Backflow prevention valve and fan module housing for a gas burner appliance, the fan module housing defining a gas/air mixture flow channel having a gas/air mixture outlet through which a gas/air mixture can be provided to a burner of the gas burner appliance, the backflow prevention valve being positioned in the gas/air mixture flow channel, the backflow prevention valve comprising: a support structure provided by the fan module housing, wherein the support structure defines at least partially said gas/air mixture outlet, wherein the support structure comprises posts being an integral part of the support structure; a valve body, wherein the valve body comprises a valve flap section acting together with a valve seat provided by the support structure, a valve mounting section and valve hinge sections through which the valve flap section is connected to the valve mounting section; a mounting bracket for mounting the valve body at the support structure in such a way that the valve mounting section of the valve body is sandwiched between the support structure and the mounting bracket, wherein the mounting bracket comprises recesses or passage openings, wherein the posts of the support structure act together with recesses or passage openings of the mounting bracket in such a way that the posts of the support structure penetrate through the recesses or passage openings of the mounting bracket and mount the mounting bracket and thereby the valve body at the support structure in a reformed status of the posts. the fan module housing defining a gas/air mixture flow channel having a gas/air mixture outlet through which a gas/air mixture can be provided to a burner of the gas burner appliance, the backflow prevention valve being positioned in the gas/air mixture flow channel, the backflow prevention valve comprising: a support structure provided by the fan module housing, wherein the support structure defines at least partially said gas/air mixture outlet, wherein the support structure comprises posts being an integral part of the support structure; a valve body, wherein the valve body comprises a valve flap section acting together with a valve seat provided by the support structure, a valve mounting section and valve hinge sections through which the valve flap section is connected to the valve mounting section; a mounting bracket for mounting the valve body at the support structure in such a way that the valve mounting section of the valve body is sandwiched between the support structure and the mounting bracket, wherein the mounting bracket comprises recesses or passage openings, wherein the posts of the support structure act together with recesses or passage openings of the mounting bracket in such a way that the posts of the support structure penetrate through the recesses or passage openings of the mounting bracket and mount the mounting bracket and thereby the valve body at the support structure in a reformed status of the posts. a support structure provided by the fan module housing, wherein the support structure defines at least partially said gas/air mixture outlet, wherein the support structure comprises posts being an integral part of the support structure; wherein the support structure defines at least partially said gas/air mixture outlet, wherein the support structure comprises posts being an integral part of the support structure; a valve body, wherein the valve body comprises a valve flap section acting together with a valve seat provided by the support structure, a valve mounting section and valve hinge sections through which the valve flap section is connected to the valve mounting section; a mounting bracket for mounting the valve body at the support structure in such a way that the valve mounting section of the valve body is sandwiched between the support structure and the mounting bracket, wherein the mounting bracket comprises recesses or passage openings, wherein the posts of the support structure act together with recesses or passage openings of the mounting bracket in such a way that the posts of the support structure penetrate through the recesses or passage openings of the mounting bracket and mount the mounting bracket and thereby the valve body at the support structure in a reformed status of the posts. wherein the mounting bracket comprises recesses or passage openings, wherein the posts of the support structure act together with recesses or passage openings of the mounting bracket in such a way that the posts of the support structure penetrate through the recesses or passage openings of the mounting bracket and mount the mounting bracket and thereby the valve body at the support structure in a reformed status of the posts.