Announcement

Collapse
No announcement yet.

80% furnace flue temperature?

Collapse
X
  • Filter
  • Time
  • Show
Clear All
new posts

  • 80% furnace flue temperature?

    We dont do residential (at least not very much), and I had a new condensing unit/furnace installed last week for a client of ours and he asked how hot the flue would get when operating.

    Its a 80% 115,000 Btu input. Not that it really matters, but now I am curious. The one I installed in my home is a 92% so its not even close to running the same flue temp.

    Regards,

  • #2
    Re: 80% furnace flue temperature?

    An 80% condensing furnace flue temp. will likely be above 275 degrees F.

    Should be vented into a Cat. III non masonary chimney without any other gas appliances connected.

    It is pretty important that this type of furnace is installed per manufactures instructions.

    Comment


    • #3
      Re: 80% furnace flue temperature?

      I am not worried about not being installed properly, he was just asking about the temp of the flue, I think he was checking it out during the first cold snap we had last week, (Heck , I just ran the gas piping ot my furnace last week).

      I am pretty sure he touched the B-vent flue piping since he said it seemed really hot.

      I was just curious as to what temperatures to expect from such!

      Thanks for the reply.

      Comment


      • #4
        Re: 80% furnace flue temperature?

        Originally posted by biscuit View Post
        I am pretty sure he touched the B-vent flue piping since he said it seemed really hot.
        Category III appliances operate with a positive vent pressure and with a vent gas temperature generally at least 140° F. above its dew point temperature. Their AFUE ranges from approximately 78% to 83%. Because the pressure in the vent exceeds that of the surrounding atmosphere, these appliances require an airtight vent to prevent leakage of flue gases before they reach the outside venting location. An example of a category III appliance would be a mid-efficiency furnace that is vented horizontally through the wall. Venting systems for category III appliances typically include high temperature plastic and single wall stainless steel metal vents.

        Originally posted by biscuit View Post
        I am not worried about not being installed properly
        Maybe you should be? B -vent is not acceptable for this type of appliance!
        You will never expand your mind, if you do not challenge your beliefs.

        By the reading of this post, you acknowledge and agree that the poster shall not be responsible or liable, directly or indirectly, for any damage or loss caused or alleged to be caused by or in connection with use of or reliance on any content contained herein.

        Comment


        • #5
          Re: 80% furnace flue temperature?

          Sorry I missed this one somehow.

          The installed furnace is a York 80%. They are considered Category 1 thus the B-vent is ok.

          Regards,

          Comment

          Working...
          X