A combustion chamber assembly unit, for a vaporizing burner, includes a combustion chamber housing with a circumferential wall extending in a direction of a combustion chamber housing longitudinal axis (L) and a bottom area (14), together defining a combustion chamber (16). The bottom area (14) includes an evaporating medium carrier (18) and on a side facing the combustion chamber (16), a porous evaporating medium (20). A first flame diaphragm (36), with a first diaphragm opening (38), is provided on the circumferential wall (12). A second flame diaphragm (40), with a second diaphragm opening (42), is provided at an axial distance to the first flame diaphragm (36) on an axial side facing away from the porous evaporating medium (20). An air admission opening arrangement (44) is provided in the circumferential wall (12) and includes an air admission opening (46) between the first flame diaphragm (36) and the second flame diaphragm (40).
