Im having issues exhausting my dryer. I cannot exhaust straight up through my roof because of clearance issues. instead the gas techs have it up 6 feet, then a 90 degree turn, 6" over and another 90 degree straight up and out. I tried eliminating the first 90 so its a 45 then 45 and out. still no go. I even installed a fan before the second 45 to help pull it out. Still not working. Please if anyone has any suggestions let me know.