Patsy K Louisville , KY July 22, 2018 Appliance: Whirlpool Microwave MH7140XFB1 Whirlpool Microwave Mh7140xfb1: Vent on microwave. How to replace Microwave Vent Grill. Just installed new vent and it worked great. Do-It-Yourself Rating: Repair Time Estimate: Less than 15 minutes