A:Answer The LG 2.2 cu.ft. Over-the-Range Microwave Oven, Model # LMH2235ST can be vented externally in one of two ways, however, do NOT vent into a wall cavity, an attic, or an unused area.
For Roof Venting, if your oven is located on an outside wall near the roof, you will need to use a 3 1/4" x 10" duct or a 6" round duct with a 3 1/4" to Round Ductwork Transition. For Wall Venting, if your oven is located on an outside wall of your house, you will need a 3 1/4" x 10" duct 6" round duct with a 3 1/4" to Round Ductwork Transition again, be sure there is enough clearance within the wall for the exhaust duct...^IFV