Donald's vent never failed. He installed a new roof and specified a GAF attic fan to be installed , in writing, during the process of the job. The contractor took it upon himself to install a cheaper exhaust fan, going against the signed contract. This is the quandry Donald is in. He wants his GAF exhaust fan because they have a very good reputation for longevity, and are maintenance free. Not to mention, the GAF is in the signed contact, which the roofer totally ignored. Basically, he got shafted by the roofer / contractor and wants it corrected.