Welcome! Here are the website rules, as well as some tips for using this forum.
Need to contact us? Visit https://heatinghelp.com/contact-us/.
Click here to Find a Contractor in your area.

Spill switch / down draft problems with Buderus GC124

joecords
joecords Member Posts: 5
Hi,

I'm having trouble with my heating system and I'm hoping this community could help. I have a Buderus GC124 that was installed 3 years ago. 2 or 3 times each heating season the spill switch will flip in the middle of the night leaving us without heat. This of course happens on the coldest nights and in particular on very windy or blizzard days. Most recently, it flipped and when I reset it and the boiler fired again, CO detectors started going off in the house, so I'm obviously concerned about the issue.

I had a plumber and chimney specialist come look at the problem and they claimed to have called Buderus who told them this unit should not be installed on an exterior wall and that the unit needed to be replaced. They did not recommend an insulated liner to resolve the issue and said a power vent would void my warranty. I don't see any mention of this in installation instructions and can't find any other information on this anywhere.

This doesn't sound right at all to me but wanted to get another opinion on whether that is true from someone with experience with these boilers. Or any other ideas on what to do to solve my issue?

Thanks,

Joe

Comments

  • HVACNUT
    HVACNUT Member Posts: 4,590
    edited November 2017
    They're right about the power vent but wrong about an exterior chimney and liner.
    First, don't let them back in your home.
    3 year old boiler needs to be replaced. Tell them to pound sand.
    Second, read pages 12 and 13 of your I&O manual. Then post back and tell us whether or not everything is in compliance.
    Post some pics also.
    We can probably pin point the problem but you'll still need a qualified tech to check the system. I.E., gas pressure, draft, and perform a combustion analysis.
  • Noel
    Noel Member Posts: 177
    edited November 2017
    Read page 100 in NFPA 54 and see where your chimney size fits for your climate. Sometimes it is allowed. Then read paragraph 13.11.1 and see if your chimney and connector are installed this way. That should help with your installation. The boiler meets code, but the installer's work might not.
  • joecords
    joecords Member Posts: 5
    edited November 2017
    Thank you very much. Unfortunately, I don't think i'm qualified to be able to quite understand the details of the I&O manual and the code to ensure it was done correctly. I believe my next step is to find an actual knowledgeable and reputable tech to check the system. I have had 3 different contractors (including one that did the original install, who is nowhere to be found) over and none have done any comprehensive checks or measurement, just seemingly trying to use intuition, make guesses at the problem and trial and error. Should I be looking for a great HVAC technician or Chimney person at this point? Any recommendations in Long Island, New York?

    I have tried using various contractor review sites and personal recommendations to very limited success. I have also found that not too many local techs are that familiar or comfortable with the Buderus equipment for some reason.

    The other thing to note is the original install was fully permitted and inspected by appropriate local authorities, so hopefully any code issues would have been use identified then.
  • Robert O'Brien
    Robert O'Brien Member Posts: 3,450
    An external masonry chimney needs to be lined with an 85% gas boiler. I would suspect insufficient combustion air or negative pressure in house
    To learn more about this professional, click here to visit their ad in Find A Contractor.
  • HVACNUT
    HVACNUT Member Posts: 4,590
    Where on L.I. are you?
    Click on the link at the top of the page for a contractor in my area. There are many on our island on this site that can help.
    Like Robert O'Brien (and the I&O manual) said, it's probably a combustion air issue.
    And like @Noel said, your gonna need a stainless chimney liner.
  • joecords
    joecords Member Posts: 5
    I'm in Massapequa. The Chimney already has a stainless steel liner. I do see one contractor listed, but would be good to get an endorsement or recommendation from someone knowledgable.
  • HVACNUT
    HVACNUT Member Posts: 4,590
    Go to the 30 mile radius. Try Scully's P & H or Mad Dog. Both are very reputable.
  • Bob Harper
    Bob Harper Member Posts: 914
    If you have UL listed CO alarms alerting you have CO poisoning by definition. The chimney must comply with the code whether Hector the Inspector called out everything or not. An exterior chimney requires a liner on an outside wall, yes. However, it must be properly sized and installed as many are not. For instance, if it is a corrugated liner, it must be derated 20% off the bat plus additional penalty for offsets other than at the base. Smoothwall liners are exempt. Insulation theoretically can help draft in really cold climates but this can be measured. Full combustion analysis by a pro certified in it is necessary here. Due to the coincidence with cold weather, look to upper level leaks in the thermal envelope of your home first while ensuring adequate makeup air and neutral pressure at the appliance.
  • GW
    GW Member Posts: 4,536
    edited November 2017
    Are you using the automatic vent damper? Try locking it open. Also get a boiler control that will keep heat in the boiler you’ll waste some fuel but have a happier life
    Gary Wilson
    Wilson Services, Inc
    Northampton, MA
    [email protected]
  • joecords
    joecords Member Posts: 5
    Hello,

    Just an update on my issue. I continue to have intermittent downdraft problems in certain weather conditions. The chimney company feels that the issue is that we have a 6-inch output from the boiler being reduced to a 5-inch liner in the chimney and that I would benefit from a larger diameter chimney and insulating with vermiculite.

    The challenge was that Buderus will not endorse that action plan due to the fact that I have a gas boiler venting to a 3 walled exterior masonry chimney. I thought this was Buderus saying the specific unit I had was not appropriate, however, they are simply saying that National Code dictates this in section 13.1 and would not give a recommendation that was not to code. If what they are saying is true, I believe it would mean a huge number of oil to gas conversions done in the Northeast were not to national code. I can say definitively that every house in my block has a gas boiler vented out a 3 wall exterior chimney.

    Is anyone familiar with this disconnect and and can comment?

    Thanks,

    Joe
  • Jamie Hall
    Jamie Hall Member Posts: 18,904
    What Buderus is saying, most likely, is that you cannot vent to an unlined exterior chimney, according to the code -- and they are right. Whether there are a number of such installations or not is quite irrelevant.

    That said, that chimney must be lined, as has been said, and must be lined correctly -- size, material, insulation.

    In the meantime, try @GW 's suggestions.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • unclejohn
    unclejohn Member Posts: 1,757
    Have you spoke with Buderus your self or are you getting second hand info.Try and get a hold of the Buderus factory rep. He should be able to make a field visit. Find out which supply house sold your unit and they should be able to get you in contact with the rep.
  • joecords
    joecords Member Posts: 5
    I spoke with Buderus directly on a 3 way call with a professional -
    I'm not getting second hand info.

    The Chimney is lined already - that is not what they are saying is against code. They are saying that pretty much any gas unit cannot be vented into an exterior 3 walled masonry chimney (whether lined, insulated, etc.) per section 13.11.1 of the code. This is surprising to me because a huge number of oil to gas conversions in the northeast would be against code then.

    Can anyone that is familiar with the code comment? I read through it and it appears to be correct, but is this a case of people interpreting the code differently or it not being enforced?
  • Noel
    Noel Member Posts: 177
    Here's the page in the NFPA 54
  • captainco
    captainco Member Posts: 592
    Sounds like you just need a good cap that won't let the wind blow down it. Field Controls makes a Star Kap that prevents downdrafts if that is the problem. There is a simple draft test a contractor can take to determine if the flue is too small. The cap would be the first step and the least expensive.
  • GW
    GW Member Posts: 4,536
    yes Jim, yet if the chimney gets cold, the gasses may not readily go where they're supposed to go.
    Gary Wilson
    Wilson Services, Inc
    Northampton, MA
    [email protected]
  • captainco
    captainco Member Posts: 592
    There is a new medicine out called Theraflue. It keeps your chimney from getting a cold and congested.
  • GW
    GW Member Posts: 4,536
    just though the old school appliances ran a hotter gas
    Gary Wilson
    Wilson Services, Inc
    Northampton, MA
    [email protected]
  • captainco
    captainco Member Posts: 592
    If you take the exit flue gas temperature below a drafthood and then measure it above a drafthood you will find most older equipment had a lower flue temperature than most new equipment, not counting condensing.

    A boiler with a 500 degree outlet temperature (better be steam) mixed with 40% dilution air from the drafthood is only 328 degrees going into the flue. This is at a -.02" draft What if the draft is -.04" and the dilution air is 50%. Now the temperature above the drafthood is only 285 degrees. With induced draft equipment the flue temperature gets higher as the draft gets higher. See attached.
    Alan (California Radiant) Forbes
  • GW
    GW Member Posts: 4,536
    I suspect there are unique physics going on with how much dilution air is getting sucked in versus temperature of gasses. I would doubt the percentage is linear but that’s above my knowledge level. Combine that with varying levels of stratification in the home, the math can get funky
    Gary Wilson
    Wilson Services, Inc
    Northampton, MA
    [email protected]
  • skoblick24
    skoblick24 Member, Email Confirmation Posts: 2
    Bumping this thread. I have the same issue and live in the same town. Was there ever a solution to this?
  • GW
    GW Member Posts: 4,536
    draft issue, you burning wood? That's an old stand by for sure.
    Gary Wilson
    Wilson Services, Inc
    Northampton, MA
    [email protected]
  • skoblick24
    skoblick24 Member, Email Confirmation Posts: 2
    Hey Gary. Not burning anything. Its been an intermittent issue for awhile. I have drilled a 4" hole thru the foundation and installed a PVC pipe to allow for fresh air direct into the utility room. I have even tired putting an in-line fan in to push the outside air into the room. I suspect my switch is a problem, so I will replace that next. Found this forum while researching and so many similarities so figure I would post. I have two CO2 detectors, one in the room and the other just outside the room. Never trip. glad the vent switch does its job, but still haven't figured out why its happening. I will also try keeping the auto vent damper always open next.