Miele DGC 6700 Operating And Installation Instructions page 154

Appliance and installation dimensions
Cut-outs for venting the Combi Steam Oven
To ensure that the Combi Steam Oven has adequate ventilation, the following
cut-outs measuring 19 11/16" x 1 9/16" (500 x 40 mm) must be made:
a in the top of the cabinet
b in the center shelf above the installation niche
The cabinet housing must not have a back panel fitted behind the installation
niche.
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