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  1. #1

    Length Of HVAC exhaust PVC pipes? Can I shorten them?

    Hello! I purchased a ranch home last year. It has central air and a high-efficiency nat gas furnace (Lennox).

    I have two white PVC pipes coming through my brick on the back side of the house. They are about 2" in diameter and are unbelievably unsightly. I imagine one is an inlet and the other exhaust. Overall, they're probably 6' in length and include a couple of 90 deg bends each.

    Is there a certain length restriction requirement for these pipes? Can I cut/shorten them?

    I have photos, will upload when I arrive home from work.

    Thanks for any help!!!

    -Nick.

  2. #2
    Join Date
    Jul 2008
    Posts
    53
    No. You should contact an HVAC specialist in your area and let them tell you if they can shorten the piping. This is not a DIY site.

  3. #3
    Join Date
    Jul 2001
    Posts
    3,112
    Each manufacturer has specific criteria for the intake and exhaust piping and how they must be routed outside the structure. Any HVAC technician can look at the equipment O/I booklet and rework the tubing.

  4. #4
    Join Date
    Jul 2008
    Location
    Denver, CO
    Posts
    4,229
    You should leave the lines alone, call a contractor out and he could give you some ideas on maybe moveing the PVC. But don't make any modifications yourself.

  5. #5
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    67,898
    Each manufacturer and size furnace have their own min length that the exhaust pipe must be. At 6', your already about at the min for most units.
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    How many times must one fix something before it is fixed?

  6. #6
    Join Date
    Jul 2001
    Posts
    3,112
    beenthere, he is concerned with the 6 foot of pvc pipe outside the house.

  7. #7
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    67,898
    Quote Originally Posted by troyorr View Post
    beenthere, he is concerned with the 6 foot of pvc pipe outside the house.
    Oh.
    I thought he was describing the run from the furnace out.

    LOL
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  8. #8
    Join Date
    Nov 2004
    Posts
    977
    I want to see the pictures.

  9. #9
    Join Date
    Aug 2008
    Location
    Burlington , Mass
    Posts
    469
    In my 24 yrs installing 90 plus furnaces I've only encountered one job out the hundreds I've done that warranted me to run horizontaly along the outside of the home, and that was about a 4 foot section. This was to satisfy the Gas inspector & manufacturer. The exhaust exited just under a window above, and at the time the code was 4 foot minumum from any window or fresh air intake. As we have real cold winter temps, the piping also had to be insulated with 3/4 inch Armaflex. I'll admit that its an ugly sight but there was no where else to go with it. The owner painted the Armaflex to match the home and it didnt look to noticeable.


    I'm sure your piping is done that way due to restrictions by the local codes and the manufacturers specs. Its best you have an HVAC contractor have a look at it, and review your options, if any.

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