Exhaust in house, Triangletube Prestige 110

Discussion in 'Boiler Forum' started by Theruler, Jan 24, 2016.

  1. Theruler

    Theruler New Member

    Joined:
    Jan 24, 2016
    Location:
    Montville, New Jersey
    I have a TriangleTube Prestige 110 natural gas boiler that was installed in 2012. There is an intermittent gas smell that we (myself, my HVAC guy and PSEG gas company) believe to be an exhaust smell meaning the gas exhaust is coming back into the house from the boiler itself. It happens when the boiler goes into standby, but not every time. My HVAC folks have been to my house several times over last few days and they say they have checked everything and there are no major health concerns and boiler is fine.

    The boiler is located in my basement in a small utility room and we generally keep that door shut. The exhaust and air intake pipes are PVC and come out of the top of the boiler, make a left turn and go right out the front of my house. The two pipes are side by side about 6 inches apart and extend about 12 inches straight out from the house. The pipes are about 30 inches off the ground. I don't think that meets specs but it never was a problem until recently. The boiler was installed by a certified dealer by the previous home owner.

    HVAC guys theory: The previous owner had a row of bushes in front of the pipes, but we removed the closest bush this fall. Now that winter is here, he thinks wind is getting into the pipes and blowing exhaust back and in some case the exhaust is going right into the intake. The bush is not there to block the wind. He installed a long straight pipe on the exhaust making it about 2.5 ft in total and then installed a 90 degree elbow pointing down and an extension of 2 .5 on the intake making it further away from the exhaust and making it lower.

    The smell is less, but still there a bit and the odd part is that our natural gas detector is going off a few times a day when we keep the utility room door closed. I open a window, ventilate for a bit and it clears out and does not go off again for hours or if we leave utility door open and a window open. This same detector never went off prior to extending the pipes and our gas provider came to our house 5 times and never found a gas leak of any kind.

    Questions: Are we in danger? Everyone is saying "no big deal", re-plant your bush to break up the wind.
    A second suggestion is to re-pipe the intake and exhaust to the side of the house or through the chimney to get it out of head-on winds. But is that really going to solve the problem? Could this be something else? A defective boiler that is pumping exhaust into house? Everything thinks it is a ventilation issue but I am not sold.

    Any help appreciated!!! Thx
     
    Last edited by a moderator: Jan 29, 2016
  2. BadgerBoilerMN

    BadgerBoilerMN Hydronic Heating Designer

    Joined:
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    Occupation:
    hydronic heating designer/contractor
    Location:
    Minneapolis
    It is not a healthy situation. This is a sealed combustion, direct vent appliance. Properly manufactured, installed and maintained such appliances mix no (zero) inside air with combustibles.

    The cross-connection of exhaust and combustion air outside the building is very bad for the boiler and can lead to all sorts of service and performance issues it can't produce a gas smell in the house under any conditions.

    We would use an combustible gas detector and run the boiler through its cycles. If you can smell it, the detector can find it.

    A combustion analyser should be used to set up and service every gas-fired appliance but more especially the high performance ModCon. During initial setup and subsequent service the sample of the intake air, during full-cycle operation including standby, should be taken to assure there is no cross connection or gas leak in the boiler cabinet itself.
     
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  4. Theruler

    Theruler New Member

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    Thank you! I am pushing the issue with my HVAC guys and insisting on a combustion analysis. Is there any other cause for the exhaust entering the house besides poor ventilation? Could it be a problem with the boiler itself such as a timing mismatch between the flame and the release of gas? They want to repipe the exhaust out the side of the house but I get the feeling that alone will not solve the problem, but will certainly cost a ton of money.
     
  5. BadgerBoilerMN

    BadgerBoilerMN Hydronic Heating Designer

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    hydronic heating designer/contractor
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    Find the leak. Vent the system according to the manufacturer's installation manual.
     
  6. Theruler

    Theruler New Member

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    That's the issue, there isn't a leak. The exhaust is coming back into the house and the thinking is poor ventilation or too little oxygen coming in for proper combustion. That has to be the issue, just have to figure it out. Unless anyone has any other ideas about what would cause exhaust to enter the house through the boiler??
     
  7. BadgerBoilerMN

    BadgerBoilerMN Hydronic Heating Designer

    Joined:
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    Occupation:
    hydronic heating designer/contractor
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    Minneapolis
  8. Theruler

    Theruler New Member

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    Care to explain what u disagree with?
     
  9. BadgerBoilerMN

    BadgerBoilerMN Hydronic Heating Designer

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    See my first response.
     
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  10. Theruler

    Theruler New Member

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    I think we are agreeing that there is a problem with combustion and ventilation. I am confused about the word "leak". I do not believe that there is raw natural gas in the house but rather exhaust coming in. Totally agree we need do get fixed asap, find venting problem and ensure combustion analysis is checked and fixed. Are you saying there is likely a leak of raw natural gas as well? That is the only thing I was unsure about your reply.
     
  11. BadgerBoilerMN

    BadgerBoilerMN Hydronic Heating Designer

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    hydronic heating designer/contractor
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    If they know how to use a combustion analyser they can, and should, find the answers in the intake, exhaust and gas component checklist.

    Get better techs.
     
  12. Theruler

    Theruler New Member

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    Thx, tech coming this afternoon with a combustion analyzer. Is combustion analysis part of the annual inspection or do most techs only do that when they think there is a problem?
     
  13. BillTheEngineer

    BillTheEngineer Member

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    Jan 19, 2011
    Location:
    Hauppauge, NY
    On sealed combustion devices, how well sealed are they?

    If the unit were turned off and the gas supply turned off, could the intake vent on the outside and exhaust ports on the outside of the home be sealed and then pressurized to see if it holds pressure? 5 PSI or less?

    Are the combustion chamber and dusting sealed well enough to do this? If so then it could be done to find the leak?

    The only other thing I can think of is the exhaust is back into the house though some other opening other than the water heater. Does it happen when there is a dryer, bathroom fan or kitchen exhaust fan on causing a lower pressure in the home?

    Seems like this should not be too difficult to determine where the source of the problem is. Also I am not sure a $12 gas detector will detect products of gas combustion. If the HVAC & PSEG techs smelled it I am surprised they (especially PSEG) left without fixing the issue. You can also have your local fire department check for gas or carbon monoxide.
     
  14. Theruler

    Theruler New Member

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    Well, got a tech who figured it out, the boiler had the wrong settings for combustion. Apparently it was set for the previous version of the boiler and not the more latest version so the air/gas mix was totally off. Tech figured out with TT on the phone and recalibrated using combustion analyzer. Apparently a tech from a different HVAC company that replaced the blower last year calibrated to old settings. Also, a 2nd issue may be impact things. The gas vent from the meter is only 1ft away from the air intake. Gotta get that moved. Hopefully PSEG will move the vent and it won't cost me anything. Hope so anyway. Thank you all for the help!!
     
  15. Dana

    Dana In the trades

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    Good luck on getting the utility to move the vent, unless it was installed after the boiler was. It's conceivable that they could move to condemn the boiler and force you to move it before firing it back up, depending on just how prickly they are about it. The folks they sent out to investigate the gas smell didn't call you on it, hopefully a request by you to for them move the vent won't turn into a Federal case.
     
  16. BadgerBoilerMN

    BadgerBoilerMN Hydronic Heating Designer

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    hydronic heating designer/contractor
    Location:
    Minneapolis
    Happy Happy
     
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