Announcement Announcement Module
Collapse
No announcement yet.
HWH exhaust backdrafts into furnace Page Title Module
Move Remove Collapse
X
Conversation Detail Module
Collapse
  • Filter
  • Time
  • Show
Clear All
new posts

  • #16
    Re: HWH exhaust backdrafts into furnace

    As the OP is in New Jersey I'm think he is under the National Standard Plumbing Code (PHCC).

    Mark
    "Somewhere a Village is Missing Twelve Idiots!" - Casey Anthony

    I never lost a cent on the jobs I didn't get!

    Comment


    • #17
      Re: HWH exhaust backdrafts into furnace

      Okay I checked both the Uniform Codes and the International Codes and it is legal under both Codes. As I thought New Jersey does use the NSPC but for gas venting they use the IFGC as such a combination vent is legal. As far as trying to help figure out what's wrong with the vent I think we need the OP to take some pictures and post them here. I also wonder at what time the vent is spilling. It is possible the vent will spill a little until the vent pipe heats up a little and starts to draft.

      Mark
      "Somewhere a Village is Missing Twelve Idiots!" - Casey Anthony

      I never lost a cent on the jobs I didn't get!

      Comment


      • #18
        Re: HWH exhaust backdrafts into furnace

        Think about this, If you have a vent thats 6" and tie a 75 gallon water heater with a 4" flu into it, do you really think that if both appliances fire at the same time there is no spillage? Is it safe? Its like trying to cram 4 pounds of bologna into a 2 pound bag, its going to "bottleneck". Where is the logic? Its just not safe and any inspector that allows that should have his head examined.

        Comment


        • #19
          Re: HWH exhaust backdrafts into furnace

          Thanks again for all the valuable input. I will take some pictures but that will be a few days away.
          The conditions when I observed the problem was after the HWH was running for a good 1/2 hour or more (kids using their shower) and the furnace had been off for a long while - it was warm out.
          The chimney has a topper but I will check for nests anyway. I'll also see if running the furnace alone vents properly.

          Comment


          • #20
            Re: HWH exhaust backdrafts into furnace

            Originally posted by rwlnj60 View Post
            Thanks again for all the valuable input. I will take some pictures but that will be a few days away.
            The conditions when I observed the problem was after the HWH was running for a good 1/2 hour or more (kids using their shower) and the furnace had been off for a long while - it was warm out.
            The chimney has a topper but I will check for nests anyway. I'll also see if running the furnace alone vents properly.
            Just as a little tip, a lit wooden match at the bottom of the draft diverter will verify a flow or lack there of.

            Mark

            BTW: A picture of the termination cap would help as well.
            "Somewhere a Village is Missing Twelve Idiots!" - Casey Anthony

            I never lost a cent on the jobs I didn't get!

            Comment


            • #21
              Re: HWH exhaust backdrafts into furnace

              UMC spells it out pretty clearly:

              For Category 1 appliances (natural draft)

              For sizing a gas vent connected to two appliances, with draft hoods, the effective area of the vent shall not be less than the area of the larger draft hood outlet plus 50 percent of the area of the smaller draft hood outlet or greater than seven times the smaller draft hood outlet.

              This is what makes vent saddles illegal. The proper way to tie 2 applianes together is with a factory made tee with reducers, or a fitting such as a 5x4x3 or 6x4x3 wye branch.

              Comment

              Working...
              X