Miele DGC 6660 Operating Instructions Manual page 163

Appliance and building-in dimensions
Cut-outs for venting the steam combi oven
To ensure that the steam combi oven has adequate ventilation, the following
cut-outs measuring 500 mm x 40 mm must be made:
a In the top of the furniture unit
b In the interim shelf above the building-in recess
Make sure there is no back wall behind the building-in recess.
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