Consumers should immediately stop using the air conditioning and heating units in the heat mode and contact Williams Corporation to schedule a free repair. Consumers should confirm whether they have one of the impacted units by checking the model number, as well as matching both the model number and serial numbers provided. For more information, consumers may contact Williams Corporation at 1-888-209-0999 between 8 a.m. and 5 p.m. ET Monday through Friday or by e-mail zonelinerecall@williamshvac.com or visit the firm's website . Consumers may also view the recall notice on the [NJS_FILE:b50b5b50-9925-4f5b-901a-439953cbbfe3:0f87fd9d-f3d6-4994-bf2d-92e98d659911]. Date modified: 2011-06-16