It has dawned on me that when Dan put this section together that it would be quite informative. Unfortunately, I don't think it is really doing our industry any good because of the lack of readers and the lack of comments. It is almost as if most people (contractors) don't read this because they don't think that a case of CO poisoning will happen to them on their watch. Ignorance is not a good legal defense in the eyes of the court.
Education is key, and anyone who deals with a flame has the exposure necessary for a carbon monoxide situation. I can name the people who will read this and comment on it on one hand, and that is not right, because as I said, ANYONE who deals with FLAME (oil, gas, coal, wood, LP etc) is in the arena of Carbon Monoxide exposure. It is not my intent to belittle people into participating on this forum. It is my intent to teach what I know in hopes of getting more and better participation, and hopefully actual participation in the field.
I am in the process of inspecting candidate boiler rooms of numerous MFD dwellings here in Colorado for possible replacement, and one key component is a review of the combustion analysis and venting considerations of existing buildings. The eventual end process here is to replace these dinosaurs with high efficiency sealed combustion systems, which doesn't completely eliminate the possibility of a CO case, but significantly alleviates it. And not all of these "candidates" will receive funding necessary to replace their dinosaur burners, and the CO potential may remain behind, so I feel it is important to address these situations.
I am certain that Timmy Mc will chime in here because I know he has a deep and great interest in educating people on CO, and how to eliminate the potential exposure, and I appreciate his input and wisdom in this delicate area.
The one common thread that I am finding on all of these projects is poor manufacturer designs as it pertains to appliance draft hoods, and inadequate/improper draft in the combustion zone that ends up creating their own set of problems as it pertains to the production of CO, and the eventual possible spillage of same. And what is even more important, is that what I am seeing in the filed is typical and representative of what is the "norm" out in the field.
Let's face it. If you have flame, you have CO. In all of my years of dragging combustion analyzers through the field, I have come across ONE appliance that had ZERO carbon monoxide in the flue gas stream, and oddly enough, that appliance was improperly applied. It was a small (< 75K tbuH) atmospheric cast iron boiler, that was missing its draft hood (bell shaped) and was directly connected to a masonry flue (unlined). And that is the ONLY appliance I have ever seen that had zero CO . Every other appliance I have inspected had CO to one degree or another in the flue gas stream.
Back to the draft issue. The fixed, integral draft relief hood, by its design and nature, is a physical disconnect between the main chimney, and the connected appliance. During my inspections last week, I was seeing ZERO negative draft at the appliance draft relief hood where flue gas samples were being drawn, and theoretically, in order for the combustion zone to work correctly, there should be at least -.02" W.C. pressure at that point.
Of the 8 natural draft appliances tested, NONE of them had ANY negative draft where they should have. There was typically a -.06 potential in the main chimney, but due to the design of the relief hood, there was nothing other than convection moving the required air through the combustion zone, and as a consequence, the excess air required for complete combustion was low, and the production of CO common.
So, we know what the problem is. What is the solution. The field "fix" is to block off the uncontrollable draft relief hood on the appliance, and install a properly adjusted double acting barometric damper on ALL appliances served by the chimney to insure that all of the appliance combustion zones are maintaining proper and required draft to do a proper and complete job of combustion. In order to do this correctly, it will require the installer to also install, or modify the roll out detection protection that is currently at the draft relief hood. Even under the utmost ideal of conditions, spillage from the relief hood is still a potential that MUST be protected against.
Now comes the scary part. Most manufacturers don't WANT us out there making field modifications of their appliances without their permission/knowledge. So I guess the question becomes, "Why are you doing what is known to not be the right thing in the first place?" Why are most all natural gas appliance manufacturers using the same known poorly operating draft relief method? Just because that is what everyone is doing does not make it right, does it? Why isn't the use of a barometric damper a standard?
I realize that the atmospheric appliance is headed the way of the Dodo bird, but there are STILL going to be a LOT of these beasts lying around in mechanical rooms throughout the world. I also realize that manufacturers probably will not comment on this issue for liability reasons.
There are significant benefits to fuel efficiency increases to be associated with this draft relief hood retrofit, and done properly, the extended liability to the contractor is really no higher than the potential exposure they are being exposed to right now.
Jim Davis with NCI has been my mentor on this subject for many years, and I am hoping that he will find his way to this thread and make comments, because I know he has had a lot of experience in this area.
There are a lot of other conditions that will cause CO production, even WITH proper draft conditions,and I would like to address those in a separate threads. I invite your comments here about the assumption of voided warranties as it pertains to field modification of the draft control systems. If you are afraid of liability, then I understand your not using your usual screen name, but please do comment. This is an area that affects everyone of us, and needs to be addressed by our industry as a whole.
Let's change this CO section from reading like an industry Obituary page to something that we can all learn from and actually save lives, AND increase efficiency and reduce energy consumption.
Lastly, many thanks to our host and his lovely wife for creating this section. Now, lets put it to use and make it do more than announce illness and death.
It's not so much a case of "You got what you paid for", as it is a matter of "You DIDN'T get what you DIDN'T pay for, and you're NOT going to get what you thought you were in the way of comfort". Borrowed from Heatboy.