(206) 949-5683, Top Rated Plumber, Seattle
Results 1 to 6 of 6

Thread: Does poor venting mean a failing water heater

  1. #1
    DIY Junior Member nrmedic's Avatar
    Join Date
    Aug 2011
    Location
    Longview, TX
    Posts
    3

    Default Does poor venting mean a failing water heater

    Newbie here. I have searched the web but cannot find a straight forward answer so wanted to ask y'all. I have 2 water heaters but noticed last week that the closet the NG one is in is very hot. Have not checked my vent pipe yet for obstrution but will tonight. I will also try the lighter test to see if the flame draws into a the vent. So if there is no obstruction in the pipe could poor updraft be a sign of a failing water heater? It is 13yrs old but never have any problems.ater is hot and plenty of it, never run out. Now I live in Texas and we are having record heat this summer so could that affect the updraft? There are days it's been 113 so I know it is hotter on the roof. The vent pipe is 4" metal and goes straight up to a dedicated gas vent out the roof. All of the websites I've read mention vent pipe obstruction but don't address what else could affect a normally well venting heater. Thank you for your time.

  2. #2
    General Engineering Contractor ballvalve's Avatar
    Join Date
    Dec 2009
    Location
    northfork, california
    Posts
    3,258

    Default

    Its a sign of poor venting. Had a few with pipes filled with crud down to about a 2" pipe. Pull a brush through it or change it out.

  3. #3
    DIY Junior Member nrmedic's Avatar
    Join Date
    Aug 2011
    Location
    Longview, TX
    Posts
    3

    Default

    Ok. Just disconnected the vent pipe. Clean with no obstructions. Roof vent also clean. Prior to this I turned the temp up so the unit would heat up. Let it run for 5 minutes and did the flame test at the vent hood. The flame blows away and not drawn in. Any thoughts?

  4. #4
    DIY Junior Member nrmedic's Avatar
    Join Date
    Aug 2011
    Location
    Longview, TX
    Posts
    3

    Default

    Also I have noticed over the past couple of years there is a light coating of this sediment that accumulates on top pf the tank. Not a soot but more like sand in appearance and texture. Think it is rust?

  5. #5
    Retired Defense Industry Engineer jadnashua's Avatar
    Join Date
    Sep 2004
    Location
    New England
    Posts
    21,382

    Default

    If the flue doesn't draw, you need to resolve that, as you're likely dumping exhaust gases into the house which if they don't kill you, can make you sick. Why it doesn't draw properly depends on many things: size, length, height relative to the roof peak, prevailing winds, whether there is actually enough make-up air, and probably things I've not listed.
    Jim DeBruycker
    Important note - I'm not a pro
    Retired Defense Industry Engineer; Schluter 2.5-day Workshop Completed 2013, 2014

  6. #6
    In the trades Dana's Avatar
    Join Date
    Jan 2009
    Location
    01609
    Posts
    2,714

    Default

    Depending on duct design & leakage, it's often the case that running the whole-house AC can put the basement under negative pressure, sucking outdoor air down the water heater flue. Try your backdraft test with the AC and all bath fans off and see if it then drafts correctly. The solution may be to seal the air conditioning ducts.

    Also, most atmospheric-drafted HW heaters use 3" vent, not 4". What's the BTU rating of the burner (or the model name/number). Oversizing the vent can also result in crummier flue draft. That might cause excessive "spillage" at the vent hood on startup before the flue came up to temp, but that alone wouldn't cause air to be pulled down the flue when the HW heater is firing. Sharing the flue with another appliance can be legal if done right, but is less than ideal.

    Since the thing is in a closet, what provisions have been made for providing combustion air?

Similar Threads

  1. question on water heater venting (orphaned water heater)
    By harveymasons in forum Plumbing Forum, Professional & DIY Advice, Tips & Tricks
    Replies: 2
    Last Post: 08-23-2010, 06:11 AM
  2. Is tub faucet cartridge failing or HW heater
    By AKRBT in forum Plumbing Forum, Professional & DIY Advice, Tips & Tricks
    Replies: 2
    Last Post: 06-28-2009, 08:13 AM
  3. Septic gas belching past full p-traps/ Septic tank drainfield failing? Venting issue?
    By ryan100 in forum Plumbing Forum, Professional & DIY Advice, Tips & Tricks
    Replies: 34
    Last Post: 10-22-2008, 06:49 PM
  4. Venting a gas water heater
    By zenn068 in forum HVAC Heating & Cooling
    Replies: 6
    Last Post: 08-02-2008, 09:43 AM
  5. water heater venting
    By perrycat in forum Plumbing Forum, Professional & DIY Advice, Tips & Tricks
    Replies: 10
    Last Post: 08-14-2007, 07:07 AM

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •