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Awareness: A little tidbit #4

 Got called to inspect a range making strong odors when operating the oven(s). Analyser showed 2400ppm and climbing coming from the oven vent. The unit was newer and recently converted to LP gas. I double-checked the conversion, got another turn or so on the hooded orifices, and found the pressure to be 10.4 inches W.C. Still way out of whack. This unit is 7000 ft above sea level, so I figure the manifold pressure can be lowered a little; change the reg to an adjustable type,try all levels of manifold pressure from 6 to 11 inches, no improvement. I figure the unit must be mis-manufactured with wrong burner parts and advise the owner to get the appropriate people out to inspect it.

 So a senior tech from (Huge Retail Appliance Store) calls me and says the oven is "perfect, it has a blue flame with yellow tips and we don't use instruments to test anything. You always gonna get high CO from the vent, so don't waste time testing there. If there's a problem with odors, you gotta get better ventilation. And besides you can't smell CO anyhow".

 To be continued.......


  • SteamheadSteamhead Member Posts: 11,383
    Once again

    you can't fix stupid!
    All Steamed Up, Inc.
    "Reducing our country's energy consumption, one system at a time"
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
    Baltimore, MD (USA) and consulting anywhere.
  • STEVEusaPASTEVEusaPA Member Posts: 1,506

    The senior tech wont be there when the disaster happens.  So where should you go from here?  Does anyone else have suggestions for the next step?  I guess they touched it last.  Who else should you involve, the fire marshall, a building inspector?  Just wondering how others have handled, or think this should be handled?

    Obviously, Plumdog is very concerned about the H/O health and well being.
  • Bob HarperBob Harper Member Posts: 732
    response to high CO

    Tag out/ lock out offending appliance. Homeowner should sign your paperwork noting appliance is 'dangerous' as defined by ANSI stds. To re-connect the appliance and operate it as is presents an immediate threat to life safety and/or fire. Recommend the unit be repaired or replaced with one that can operate within the mfrs. specs and industry stds. Also recommend an unlisted low level CO monitor.

    The appliance's gas line should be disconnected and capped and the operating control disabled such that both require tools to place it back into operation.
  • icesailoricesailor Member Posts: 7,265
    CO Tid Bit:

    If I am faced with a situation like that, if I can't resolve it, and some cretin tried to BS me with a story like that, I call tech support for the manufacturer and get someone who knows what they are talking about. I ask them what THEY are going to do about it.

    Point out that 2400 PPM when the oven is on.
  • Jim DavisJim Davis Member Posts: 578
    Oven CO

    I find that if the manufacturer knew anything about oven problems they wouldn't make them (unvented) in the first place.  The legal amount an oven can produce according to ANSI Z21 is 800ppm "Air Free".  Air Free means no O2 in the sample.  Most ovens have 12%-14% O2 in their vent.

    Gas at higher altitudes is already de-rated that the old standard of reducing input may not be the best thing to do.  The burner flames on most ovens hit directly on a piece of metal called a spreader plate.  Anytime flames hit metal they will burn dirty initially.  However if the metal can be heated up over 1000 degrees the CO is now able to burn completely. 

    On most LP ovens that I have experienced, low fuel was more the problem than high fuel.  It is possible the oven is defective but I have found very few that couldn't be adjusted so the CO is below 50ppm.
  • SteamheadSteamhead Member Posts: 11,383
    edited June 2012
    We recently started working with an apartment complex

    recently under new management, in which pretty much everything had been knuckleheaded. So far they have had two (UL listed) CO detector activations caused by oven burners in stoves. In one case, the CO in the oven flue was 774 PPM air-free- just below the archaic standard mentioned above. Some simple cleaning and adjustments fixed this one- on the other one the stove was in generally poor condition so they just replaced it.

    I've recommended that we test all the stoves in the complex. We'll see if they go for it.

    While there I told them my two favorite stove CO stories, repeated here for your enjoyment:

    1. My house has always been in the family. In 1968 or so, my grandmother got a new Norge gas stove from the gas company. She was so proud of her new Norge! For years she cooked for us on that Norge when we came to visit, and there was always a warm, fuzzy feeling in her kitchen.

    Now I have the house, and the Norge is still working, but now it's working properly.

    When I got my first analyzer, I tested that stove- and found the oven was putting out 1100 PPM air-free! That explained the warm, fuzzy feeling :-O  The burner only needed to be properly adjusted to bring the CO down.

    In 1968, they had some chemical CO detectors that would alert if the CO rose above a certain threshold- not the digital analyzers we all have (or should have) today. That's the only possible excuse for these CO levels. Also, houses had much more air infiltration than they do now. That's probably why we never had a possible CO event.

    2. Some ten years ago, I went to see one of my neighbors- not on a work-related issue, at least initially- and when she opened the front door, I got a strong blast of aldehyde odor. I asked her where it was coming from, and she said she had just turned the oven on. I told her to shut it down and open the windows, and that I'd be back.

    I went home, got my analyzer and some hand tools and returned. The kitchen was in the back of the house, and the stove was an older Tappan (but looked newer than my Norge). The oven was putting out over 2500 PPM air-free! I shut the analyzer down before it got any higher. Took me a bit longer to get this one working properly, but eventually I got it into adjustment. She said everyone she talked to said the odor was normal- I hate to think how many people she knew that were getting high CO in their homes.

    Several years later, this was the house where I first met The Lovely Naoko. So if I hadn't fixed that stove, there is a chance I would not have met my wife!
    All Steamed Up, Inc.
    "Reducing our country's energy consumption, one system at a time"
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
    Baltimore, MD (USA) and consulting anywhere.
This discussion has been closed.


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