My parents called and can't get any heat out of it. My Brother's, mine and theirs are identical. The only difference is mine and my brothers have 6-7 feet vertical rise before the horizontal to the outside . Theirs is straight horizontal to the outside. I was guessing maybe the wind is blowing back on the pipe causing the combustion blower to work harder? I will check the feed rates Friday .I replaced the combustion blower and control board last year and door gasket last week. Any Big E owners have any suggestions?