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  1. #27
    Join Date
    Mar 2004
    Location
    Cabot, PA
    Posts
    177

    CLEARLY EXCEEDS MAXIMUM

    Should have been all 3 inch I dont see anywhere on that table that mentions going from 2" to 3" and the back to 2"

  2. #28
    Join Date
    Jan 2006
    Location
    Minneapolis, MN
    Posts
    70

    Re: CLEARLY EXCEEDS MAXIMUM

    Originally posted by mechanicalmaster
    Should have been all 3 inch I dont see anywhere on that table that mentions going from 2" to 3" and the back to 2"
    The instructions do say:

    8. All piping through the roof is 2". When using 3" pipe, reduce to 2" within 18" of the inside of the roof.

    However, the current reduction is way, way far from roof...

  3. #29
    Join Date
    Jul 2002
    Posts
    962
    I didn't notice in your OP, it is a modulating furnace. I never installed one, but from what you showed us, they should have run 3" all the way, or run it out the wall if possible. I guess the modulating furnaces are a little more critical on venting.

    Get them back out there and have them do it right!

  4. #30
    Join Date
    Aug 2002
    Posts
    1,651
    I hate to see any sealed combustion furnace have only the exhaust pipe run.. I never have installed a sealed combustion furnace and not installed a combustion air..

    I agree, it looks like the need to rerun the pipe at the correct size.. also have them run the intake pipe.. Money well spent in my opinion..

    Good luck
    J

    We are a critical bunch,,, you want more comments,,, just post more pictures of the whole install.. lol..

    p.s. I hope you got a Mod t-stat with your furnace, so you can take for advantage of Mod furnace..

    [Edited by Advanced Response on 02-14-2006 at 07:38 PM]

  5. #31
    Join Date
    Jan 2006
    Location
    Minneapolis, MN
    Posts
    70
    Originally posted by Chill
    I didn't notice in your OP, it is a modulating furnace. I never installed one, but from what you showed us, they should have run 3" all the way, or run it out the wall if possible. I guess the modulating furnaces are a little more critical on venting.

    Get them back out there and have them do it right!
    Thanks to everyone. I will call the installer and bring this to a resolution. If I have enough energy left, I'll return to tell the rest of the story. I didn't realize that replacing an HVAC system could be so draining! Seriously, I am extremely grateful for this forum's help!

  6. #32

    Non-Direct Vent Combustion Air

    Its really a matter of choice weather you want to install a two pipe system or a single pipe system. As long as you have enough make up air you should be ok. I installs a single pipe system my self.

    regards,
    Kelvin Lyons

  7. #33
    Join Date
    Nov 2005
    Location
    Kansas
    Posts
    4,449

    Re: Non-Direct Vent Combustion Air

    Originally posted by klyons20
    Its really a matter of choice weather you want to install a two pipe system or a single pipe system. As long as you have enough make up air you should be ok. I installs a single pipe system my self.

    regards,
    Kelvin Lyons
    1. Do you realize how much cold air you pull into the house for the combustion?
    2. In a house are often chlorines used (laundry) that will damage the heat exchanger as well.
    When ever possible you always should install a two pipe system.

    This piping system is a clear code violation and needs to be replaced at no charge by the installer. You paid for an installation installed by industry standards.

  8. #34
    Join Date
    Nov 2004
    Location
    SW FL
    Posts
    6,440

    Re: Re: Pressure ?

    Originally posted by trane
    Originally posted by dan sw fl
    Originally posted by jeff-4
    In the install, they patched into an existing 2" vent.

    The setup is 3" PVC from the furnace through an elbow to a 3"-2" contraction, then into existing 2" pipe.

    All looks very nice, except I noted from reading through the installation manual.

    , the existing 2" vent run has 6 elbows and runs for a total of at least 20 feet. So, the new vent line has about 12 feet of 3" pipe including one elbow then about 20 feet of 2" pipe with 6 elbows.
    What is the back pressure?

    What is the allowed pressure?
    Ask TECH Support at mfg.

    The NEW installation IS Better than the old one.

    Does the original contract
    specify .."ENTIRE new 3" vent line will be installed" ?

    You wish to have 3" diameter ...
    Set-up another contract and Pay.
    Why should he have to check the quote back pressure?
    How do you know this installation is better? Every brand has different rules for the venting.

    Why does a homeowner need to verify in righting that its going to be installed according to the installation instructions and specifically the venting when he has no idea what the requirements are?

    [Edited by trane on 02-14-2006 at 06:48 PM]
    Why should he have to check the quote back pressure?
    .......
    To KNOW if the existing installation is acceptable! !!
    It ought to take less than 3 minutes to make a measurement.

    Is the Existing back pressure perhaps
    ALREADY < 1/2 of the Maximum Permissible?

    INSTRUCTIONS are Guidelines, NOT Requirements.

    It appears that the 2" PVC has been there for 20 years.

    "Why does a homeowner need to verify in writing that its going to be installed ...?"
    ALL Changes must be noted,
    unless a H.O. wishes make a second payment
    for items outside the scope of the original contract.
    Designer Dan
    It's Not Rocket Science, But It is SCIENCE with "Some Art". ___ ___ K EEP I T S IMPLE & S INCERE

    Define the Building Envelope and Perform a Detailed Load Calc: It's ALL About Windows and Make-up Air Requirements. Know Your Equipment Capabilities

  9. #35
    Join Date
    Mar 2004
    Location
    Cabot, PA
    Posts
    177

    Re: Re: Re: Pressure ?

    [i]Originally posted by dan sw fl






    INSTRUCTIONS are Guidelines, NOT Requirements.

    It appears that the 2" PVC has been there for 20 years.


    [/B]
    I don't care if it has been there 20 years or not it does not meet the requirements of the new equipment so needs to be corrected.

  10. #36
    Join Date
    Jul 2004
    Location
    midwest
    Posts
    2,868

    Re: Re: Re: Pressure ?

    [

    [Edited by trane on 02-15-2006 at 08:13 AM]

  11. #37
    Join Date
    Jul 2004
    Location
    midwest
    Posts
    2,868

    Re: Re: Re: Pressure ?

    Originally posted by dan sw fl
    Originally posted by trane
    Originally posted by dan sw fl
    Originally posted by jeff-4
    In the install, they patched into an existing 2" vent.

    The setup is 3" PVC from the furnace through an elbow to a 3"-2" contraction, then into existing 2" pipe.

    All looks very nice, except I noted from reading through the installation manual.

    , the existing 2" vent run has 6 elbows and runs for a total of at least 20 feet. So, the new vent line has about 12 feet of 3" pipe including one elbow then about 20 feet of 2" pipe with 6 elbows.
    What is the back pressure?

    What is the allowed pressure?
    Ask TECH Support at mfg.

    The NEW installation IS Better than the old one.

    Does the original contract
    specify .."ENTIRE new 3" vent line will be installed" ?

    You wish to have 3" diameter ...
    Set-up another contract and Pay.
    Why should he have to check the quote back pressure?
    How do you know this installation is better? Every brand has different rules for the venting.

    Why does a homeowner need to verify in righting that its going to be installed according to the installation instructions and specifically the venting when he has no idea what the requirements are?

    [Edited by trane on 02-14-2006 at 06:48 PM]
    Why should he have to check the quote back pressure?
    .......
    To KNOW if the existing installation is acceptable! !!
    It ought to take less than 3 minutes to make a measurement.

    Is the Existing back pressure perhaps
    ALREADY < 1/2 of the Maximum Permissible?

    INSTRUCTIONS are Guidelines, NOT Requirements.

    It appears that the 2" PVC has been there for 20 years.

    "Why does a homeowner need to verify in writing that its going to be installed ...?"
    ALL Changes must be noted,
    unless a H.O. wishes make a second payment
    for items outside the scope of the original contract.
    __________________________________________________ ________
    I doubt the home owner knows how to check the pressure and is not the one to do so.

    If they are only guidelines why include them? I disagree, the manufacturer has done research to know what can and can't be done with the furnace for its safe and reliable operation.

    All manufacturers have different requirements for the total length allowed on the pipes. What worked on the old does not mean it will work on the new.

    You think a homeowner getting bids for a new furnace needs to verify every detail? If it doesn't mention reconnecting the gas line that's not included? I think several things are implied when quoting a change out and one is that it will be installed according to the manufacturers install instructions and that it meets code.

  12. #38
    Join Date
    Apr 2004
    Posts
    7,680
    Kudos for actually looking at the venting tables, however, you might want to read the whole instruction rather than just the tables itself. They are there for a reason, and that reason is not just to make your life difficult.

    First you will find that non-direct vent or single pipe is only allowed on vertical venting, you need to have a two pipe system on side wall applications. Next we need to know the outside information, is it standard or alternate? This means does it need to gooseneck up to get 12" above anticipated snow level or not? If so, you need to consider that. That plays into the total length.

    Next, you need to make 2 reductions, 3 to 2" and then to 1.5" (this depends on how it's terminated again). Remember this furnace fires down to 40% and needs that velocity to clear the combustion air and overcome 40mph winds.

    If you're going to have your contractor back, he might as well do it right the second time. Dont forget to have the proper drain assembly installed on the inlet pipe while he's at it.

    As far as you're concerned this is non-negotiable. You bought a premium product and expect it to be installed properly. I'd hat to think of buying a new caddilac and having the tires replaced with some old raggedy ones off a chevette.

  13. #39
    Join Date
    Jan 2006
    Location
    Minneapolis, MN
    Posts
    70

    Re: Re: Non-Direct Vent Combustion Air

    Originally posted by tostaos
    Originally posted by klyons20
    Its really a matter of choice weather you want to install a two pipe system or a single pipe system. As long as you have enough make up air you should be ok. I installs a single pipe system my self.

    regards,
    Kelvin Lyons
    1. Do you realize how much cold air you pull into the house for the combustion?
    2. In a house are often chlorines used (laundry) that will damage the heat exchanger as well.
    When ever possible you always should install a two pipe system.

    This piping system is a clear code violation and needs to be replaced at no charge by the installer. You paid for an installation installed by industry standards.
    Hey, thanks for the info. Your statements lead me to the question of whether to ask that they install an inlet pipe. This installation replaces a system that simply used a passive 6" vent for make-up combustion air. (There is also a water heater in the furnace room.) Currenlty, the new furnace draws combustion air from the room. I can really feel the draft through the passive vent when the furnace kicks in to high.

    So, if they are coming back to fix the outlet pipe, is it worth it to add a separate inlet pipe? Since they told me that they were going to use the current approach in their bid, I would, of course, be compelled to pay extra for the inlet pipe. Again, in your esteemed opinions, would this be worth it?

    Thanks!

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