In case your over-the-range microwave oven has an interior recirculating port, then the built-in charcoal filter loses efficacy as time passes. This happens gradually — and replacing the filter is a chore many homeowners overlook. By installing an outside vent duct throughout the kitchen wall, you will ease your cleanup chores and assist eliminate heat, heat and moisture out of the kitchen.
Removing the Microwave
Open the wall cupboard next to or over the fridge and unplug the power cord. Remove the glass plate and some accessories from within the fridge and shut the door. Have a helper service the microwave and then use a Phillips head screwdriver to remove the supporting screws driven through the side walls of the next wall cabinets.
Lift the back of the microwave off the tabs on the rear wall-mounting plate with the help of your assistant and place it at the counter. Take care to feed the power cord through the hole at the side cabinet whilst doing this. This will show the microwave wall-mounting plate fitted with various openings.
Explain the port cut-out location by marking the four corner holes surrounding the opening with a pencil. Use a nut driver to remove the toggle bolts securing the mounting plate to the wall and then lay the plate apart.
Cutting the Vent Opening
Use a straightedge to join the marks enclosing the planned vent opening on the wall. Cut through the columns that are marked on the drywall with a utility knife and then trim the edges neatly. Drill corner pilot holes through the wall with a very long 1/2-inch masonry piece (for stucco siding) while keeping the cordless drill flat and at 90 degrees to the wall.
Go outside. Use the straightedge and pencil to mark the opening by connecting the exterior borders of this corner pilot holes. Use a 1/4-inch masonry bit to drill a series of closely spaced holes through the stucco and plywood wall cladding. Be careful to maintain the holes lined up with the inside border of the marked opening, and make certain that you maintain the drill flat and at 90 degrees to the wall when doing this.
Carefully remove the stucco within the opening with a hammer and cold chisel. Once removed, use tin snips to trim off the chicken wire stucco backing. Remove the remaining wall cladding with a hammer and wood. Once removed, trim the edges of the opening to permit the port cap to fit snugly into the opening.
Wear a pair of work gloves and take out the fiberglass insulation from in the opening. Dry fit the port cap to be certain it fits correctly.
Converting the Fan for Outdoor Exhaust
Go back indoors and unscrew the exhaust fan mounting plate in the microwave. Lift from the exhaust fan engine. Utilize the tin snips to cut off the marked exhaust holes to the upper-rear face of the back panel.
Expand the fan engine so the fans faces the rear wall. Reinsert the exhaust motor into the microwave, with the fans facing the newly cut exhaust holes. Secure it with the screws removed earlier.
Put in the exhaust diverter assembly provided with the microwave by clipping it to the back of this wall-mounting plate removed before. Make sure that the flaps to your diverter proceed under the flanges and then under the tabs on the back of the mounting plate, with the diverter flaps facing towards the port opening. Secure the diverter plate to the wall mount by driving the self-tapping screws provided through the matching mounting holes.
Vent Cap Installation
Gauge the distance from the lip of the outer wall opening to the microwave mounting plate. Transfer this measurement to the oval duct department attached to the port cap and mark the cut line with a felt pen.
Wear heavy gloves and then utilize the tin snips to carefully trim the duct section to the necessary length. Dry fit the port cap and then mark the place of the corner mounting holes to the stucco. Slide the vent cap out and then utilize the 3/16-inch masonry bit to drill 1-inch deep mounting holes in the wall. Harness four 3/16-inch wall anchors into the holes.
Mount a tubing of outdoor excellent silicone sealant to your caulking gun and also run a zigzag bead of silicone onto the rear-facing flange of the port cap. Slide the vent cap into position and fasten it with the bolts provided with the anchors. Wipe off excess silicone with a damp rag. Run a thin bead of silicone caulk on the joint between the stucco and the port cap to complete the mounting process.
Microwave Installation
Reinstall the microwave wall-mounting plate with fresh toggle bolts.
Lift the microwave with the help of your assistant. Feed the power cord through the hole at the side cabinet and hook the rear of the microwave onto the tabs onto the wall-mounting plate. Have your assistant support the microwave while you reinstall the mounting screws through the side walls of the next wall cabinets.
Plug the power cord back into the wall outlet and replace the microwave’s glass plate and any accessories. Fill a microwave-proof cup with water and place it within the fridge. Close to the door. Turn on the microwave on and after that check for air motion on the exterior vent cap opening to make sure the port and fan are functioning correctly.