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Thread: Liner

  1. #1
    Join Date
    Oct 2005
    Posts
    4

    A Liner Question For The Pro's

    Hello - Can you please tell me if I should have a flue liner installed for my "orphaned" water heater? My water heater is a 50 gal. 40K btu unit using 3" pipe going into the old 6-1/2" metal flue. The flue is about 15' in total height. When I bought the house, the previous owner had a high efficiancy furnace installed (PVC to outside) but did not touch the flue besides capping off the old furnace pipe entrance. Thank you. J

  2. #2
    Join Date
    Oct 2005
    Posts
    4

    Unhappy

    Wrong forum?

    Tough question?

    Helloooo...?

  3. #3
    Join Date
    Feb 2005
    Posts
    655

    Orphaned water heater


    I would strongly recommend that 6 1/2" flue be lined for that water heater.
    What is the lateral distance of connector from chimney
    to heater?
    I have a chart from Company that manufactures Z-flex
    chimney liners that will tell you exactly what size you need.
    We need BTU input,number of appliances,hight of chimney
    and distance of lateral connector.
    I will be glad to help.

  4. #4
    Join Date
    Apr 2004
    Location
    Bartlett, IL
    Posts
    6,619
    Sounds like you have a short run of B-vent connected to the water tank for venting.

    It should be OK.

  5. #5
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    68,064
    NFC permits a 3" vent gas appliance to be connected to a 7 x 7 (49 sq. in.) chimney, so by national your within code, your local code maybe different.
    Contractor locator map

    How-to-apply-for-Professional

    How many times must one fix something before it is fixed?

  6. #6
    Join Date
    Feb 2005
    Location
    Toms River, NJ
    Posts
    425
    You should check for proper draft. A minimum draft of negative 0.02 inches W.C. to a maximum draft of negative 0.06 W.C. must be maintained. This draft should be measured two feet above the appliance vent outlet. You may need to install a barometric damper to mainain proper draft.

    I strongly advise relining the chimney with a properly sized liner system.

    Dave in NJ

  7. #7
    Join Date
    Oct 2005
    Posts
    4

    Smile

    Thanks for the replies. I have only 1 appliance, (the 50 gallon 40,000 BTU water heater) connected, that feeds into 40 inches (lateral distance) of 3" pipe which then dumps into the side of a 10 inch long (lateral distance) 6-1/2 pipe before heading strait up into the last 15 feet of 6-1/2 pipe. I dont know if the Minnesota winters (-40 sometimes) would have any impact on this. What do you all think? Thanks again. -J

  8. #8
    Join Date
    Feb 2005
    Posts
    655

    Orphaned water heater

    First of all the codes do differ from place to place,
    here in Massachusetts which is relatively strict,you venting into masonary chimney with orphaned water heater would not be allowed.
    You might think it would not be a problem with that nice
    big chimney but it is a problem,inadequate draft from
    these situations can be very serious.
    Running a 4" alluminum z-flex liner( according to the z-flex chart,3' to 4' latteral, 40,000 input and 15' chimney
    hight)would be used.Material cost is low.
    http://www.houseneeds.com/shop/misc/....asp?WT.srch=1

  9. #9
    You'll be fine. The B-vent is insulated and the air going up the draft hood is going to facilatate the draft.

    Although I'd go to a 4" connector just to get the max air up the draft hood.

  10. #10
    Join Date
    Feb 2005
    Posts
    655

    venting artical

    The dynamics of drafting are complicated. Traditional masonry chimneys were designed and sized to vent very hot flue gases from old coal, wood burning, or low efficiency gas furnaces. Chimneys are like water pipes, they can only handle so much exhaust at a given pressure. Imagine if the huge boilers of your local power plant tried to exhaust up your house chimney. There simply wouldn't be enough room to handle all the smoke and ash. On the contrary, if you tried to exhaust your furnace and hot water heater into a power plant chimney, the exhaust gases very likely wouldn't rise. The column of cold, dense air inside the huge chimney could cause a portion of the exhaust gas to spill back into your basement.

    Herein lies the problem. Your chimney's existing flue liner may be oversized for the orphaned hot water heater. This can, in some instances, create condensation problems inside of masonry chimneys. Water vapor is a byproduct of the combustion of natural gas. If the inside of the chimney cools down too much or there is too much cold air inside the chimney, the water vapor can condense and saturate the masonry inside the chimney before it can escape into the atmosphere. Sometimes the condensed water contains acids that can chemically attack poor quality mortars.

  11. #11
    Join Date
    Apr 2004
    Location
    Bartlett, IL
    Posts
    6,619

    Wallynut...

    How bout reading a bit more closer...this is NOT A MASONRY CHIMNEY!! You've been rambling about the masonry chimney for a while now...re-read!

  12. #12
    Join Date
    Feb 2005
    Posts
    655

    2hot2coolme

    So you think regardless of the size of this B-VENT,
    everything is just fine. Try google orphaned water heaters
    and see what people who understand these situations say.
    My point is for the relative low cost of a liner, I
    would never take a chance. JUST MY OPINION

  13. #13

    Re: 2hot2coolme

    Originally posted by wallynut
    So you think regardless of the size of this B-VENT,
    everything is just fine. Try google orphaned water heaters
    and see what people who understand these situations say.
    My point is for the relative low cost of a liner, I
    would never take a chance. JUST MY OPINION
    You are wrong and every ventliner aB-vent mafg. says so.

    Like the man siad earlier, 7x7 chimney area.

    And let me ask you this: Would yo attempt to run a liner down a B-vent chase? It'll hang up.

    My buddy tried it and and ended up plugging the B-vent cause it got jammed.

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