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Chimneys and Flues

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Comments

  • captainco
    captainco Member Posts: 792
    A drafthood was certified using 5 foot of vertical pipe and two elbows. Drafthoods operate safe with 40% to 50% dilution air. Drafthood equipment or any equipment for that matter have ever been approved to be common vented with other equipment. Which of these are actual field conditions?
    100% of rust and corrosion are caused by improper venting. This applies to all types of equipment not just drafthoods.

    MikeL_2 - Plumbers are some of the smartest techs I know. I worked with a plumber for years that was the A.O. Smith commercial warranty rep in my area.
    A.O. Smith commercial water heaters were the first thing that required a combustion test by the manufacturer for warranty. I helped him with all his start ups and sometimes discovered problems or defects on new equipment. Because A.O Smith listed the combustion numbers they wanted, most plumbers wrote numbers down within the ranges and never did a test.

    I think the industry may think plumbers are dumb and I even joke about that in class but then I will let them know they are some of the smartest students I have ever had. Of course anyone that wants to learn 21st century knowledge is pretty smart.
  • captainco
    captainco Member Posts: 792
    I truly want this to be educational. Outside the NCI training class we can only go so far with certain information but we try to be as helpful as possible. Trust me there have been magazine articles, technical bulletins, You-tube videos, other training manuals, that have denounced our training indirectly. Even RSES and GAMA. Their biggest problem to date is they have not and can not prove that anything we teach is wrong or mechanical unsafe. This covers more than 35 years of them trying.

    Anyway I am not trying attack anyone nor do I believe any comments are attacking me, If any thing things only make me try harder to figure out what I need to do to make things more clear.
    STEVEusaPArealliveplumberMikeAmannEdTheHeaterMan
  • ChrisJ
    ChrisJ Member Posts: 15,506
    captainco said:

    I truly want this to be educational. Outside the NCI training class we can only go so far with certain information but we try to be as helpful as possible. Trust me there have been magazine articles, technical bulletins, You-tube videos, other training manuals, that have denounced our training indirectly. Even RSES and GAMA. Their biggest problem to date is they have not and can not prove that anything we teach is wrong or mechanical unsafe. This covers more than 35 years of them trying.

    Anyway I am not trying attack anyone nor do I believe any comments are attacking me, If any thing things only make me try harder to figure out what I need to do to make things more clear.

    I would hope everyone here understands that, I know I do.
    But I'm still not understanding what is actually unsafe about a drafthood.

    You mentioned rust and corrosion. Is that the danger? Damage to flues over time?

    Single pipe quasi-vapor system. Typical operating pressure 0.14 - 0.43 oz. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment
  • MikeL_2
    MikeL_2 Member Posts: 485
    edited March 2022
      Captainco,
             I'm certain no one here is on the attack. The beauty of this forum is the discussion that is generated provides an opportunity for sharing & learning.
             Some of my best friends in the Plumbing trade are creative thinkers that possess & practice common sense; important & valuable qualities in my opinion. My point was that none of us are the reigning authority..........
  • captainco
    captainco Member Posts: 792
    Chris - 1980 I was testing a boiler on an energy audit. Back then, t.here were no digital CO analyzers but my digital analyzer had a port on it to insert a CO tube that changed colors on a timed test and could approximate CO levels from 50 ppm to 5000 ppm. Thinking to myself, I decided that just leaving the tube in for the whole test might even pick up lower levels. It was much to my surprise that after 20 minutes of boiler run time the CO went from 0 ppm to 5000+ ppm. I the tube out and put another one in and it jump to over 5000 ppm immediately. What happened? The draft in the flue was -.06" w.c. That indicated a good flue and plenty of combustion air. However the burner were running out of combustion air. I didn't know that at the time nor did anyone else I called for help. Back then we were adding hot water reclaimer coils to boilers and increasing their thermal efficiency 8-12% based on a computer program I was using. Later I realized that was funky but it didn't matter. In order to do this the drafthood had to be blocked off so the flue gases weren't diluted before entering the coil. Then a gas barometirc was added above to control draft. I told the contractor if he sold the job I would be there for the start up and adjustment and try to figure out the CO problem. But the CO problem was gone and I couldn't make it come back with the new modification. This is when my combustion testing for CO radically changed and I started to investigate the function of a drafthood.

    What I discovered is that when you have drafthood equipment the flue sizing is based on 50% flue gas and 50% dilution air. This occurs when the draft is -.01" to - .02" When draft exceeds -.02" dilution air is usually increased and takes up room that the flue gases needed. Now a certain percentage of flue gases back up in the equipment. Flue gases are mostly CO2. CO2 is heavier than air and starts blocking the entrance of air into the heat exchanger. Initially because it took a while sometines for the CO to register on my CO tube, I started to pay more attention to the O2 reading. And sure enough, it would start falling slowly if this was occurring.

    We have two definitions of drafthood interference - Eddy current effect (mushroom hoods) or door curtain effect (built in or rectangular hoods.)

    If you see rust on equipment you have this problem. But it can be intermittent because sometimes the draft is lower. I actually shocks me when I see a drafthood appliance running safe. But that is an indication it is pulling excess flue gases from the equipment which it is supposed negate.

    If people would Google Jim Davis Combustion or Jim Davis Carbon Monoxide you will find many hours of reading. I am not the engineer, the Fire Chief, Cartoonist, Nuclear engineer etc, I am a proud High School graduate and Vietnam veteran and today a proud instructor at NCI. Most of other instructors listed were either initially taught by me or used materials I had written. However when you don't teach the whole truth because you might offend someone I am not sure of your morals or goals!
    STEVEusaPAMikeAmannEdTheHeaterMan
  • captainco
    captainco Member Posts: 792
    MikeL_2 said:

      Captainco,
             I'm certain no one here is on the attack. The beauty of this forum is the discussion that is generated provides an opportunity for sharing & learning.
             Some of my best friends in the Plumbing trade are creative thinkers that possess & practice common sense; important & valuable qualities in my opinion. My point was that none of us are the reigning authority..........

    Was you say is not an opinion as far as plumbers are concerned. In my world it is a fact!!
  • DJD775
    DJD775 Member Posts: 247
    edited March 2022
    captainco said:


    If people would Google Jim Davis Combustion or Jim Davis Carbon Monoxide you will find many hours of reading.

    Been Googling just that since this thread started. Lot of information posted out there on the interweb. As a DIYer I find it very interesting (and disturbing) that some of your observations contradict what is published by some trade organizations and codes. Some of these concepts seem hard to grasp when looking at it from physics perspective but I do realize that there are many physical effects taking place that are hard to account for unless you do real world testing.
    And when I mentioned disturbing earlier I'm not referring to you, I'm referring to the potential misguidance in the reference documents and codes.
    MikeAmann
  • mattmia2
    mattmia2 Member Posts: 9,473
    So that's why increasing the size of the vent connector helped, it gave the excess air someplace to go.
  • captainco
    captainco Member Posts: 792
    In 1992 when I was testing in the field with AGA I was told we could not test equipment if it was windy outside, raining or snowing. This was against industry testing standards. If one researches and studies and tests you begin to realize that none of the materials that have been written on how to install or test equipment were written by people who never worked in the field.

    In 2005, GAMA (Gas Appliance Manufacturers Association) in their magazine, stated that they could use some persons on the Code Board that actually worked in the field. People with hands on experience might add something to the Code. Really!!

    In 2000 ASHRAE did an actual field study that current combustion standards don't work under many field conditions and that Code does not allow for professionally installed systems.
    In 1995 ASHRAE did a study showing that outside air directly piped to burners was not a good idea in cold climates.
    In 2007 ASHRAE did a study that stated derating gas furnaces at altitudes up to 7000 feet was unnecessary.

    Guess what has changed? Nothing!

  • captainco
    captainco Member Posts: 792
    mattmia2 said:

    So that's why increasing the size of the vent connector helped, it gave the excess air someplace to go.

    That would be correct to say if the excess air and the flue gases made an agreement with each other. Dilution air needs to be controlled not just given more room and not operate under random selection.
  • MikeL_2
    MikeL_2 Member Posts: 485
       I'm at a loss. Is my experience with orphaned water heaters and too large a chimney behaving exactly as described by several industry experts just an anomoly?
  • Bob Harper
    Bob Harper Member Posts: 1,030
    Follow this logic: You create the means to fire a burner using pressurized gas and adjust the burner flame visually but it's match lit each time. You open the cock and toss in matches until it ignites. Sometimes ignition delays as gas builds up then a hazardous delayed ignition causes burns or equipment damage. It would be nice to have a standing flame (pilot) to ignite it for you without having to reach in and risk burning yourself. You rig a manual pilot, but it often goes out because the chimney is directly connected and downdrafts or flow reversals happen. You invent a flame proving device (thermocouple) that ensures the presence of a viable flame before the automatic gas control allows gas to flow to the main burner. In the event of wind gusts, the pilot still blows out. You figure out that disconnecting the stack allows some of the flue gases to find the stack to vent but also allows the flue gases to 'burp' out into the room instead of snuffing out the pilot (probably more commonly CO2 displacing the O2 instead of actually blowing it out). However, a lot of the fumes escape. Still, this is not perceived as a problem because the houses leak like a sieve--for a while. You rig a funnel that captures most of the fumes normally but allows burping. After a while, you realize the pipes aren't rotting out as quickly as they used to due to the dilution air. All is well and it is codified. Meanwhile, the houses have gotten much tighter with the advent of plaster interior walls then drywall and early insulation. Then the '73 War, lines at the pumps, we begin building houses differently. People begin getting sick and crazy from the indoor pollution because the house changed but the venting did not. Draft hoods do not belong in modern structures. They can also kill in cabanas and other outdoor locations. Yet, they not only remain legal but required as noted by the strong language not to mess with or replace the OEM ones. Finally, a little sensible language is drifting in that allows "other" means of draft regulation and dilution air (spelled "barometric damper"). These provide momentary relief but allow for the placement of a spill switch to guard against a sustained flow reversal. They do not kill the draft at standby and add only what is needed to sustain a minimal draft without sucking all the heat out of the heat exchanger or causing a "curtain effect" the way hoods can.
    Now ask yourself why a CAT I water heater with a draft hood is not required to have a spill switch, but boilers and furnaces do. Codes can kill and do not guarantee performance.
    Larry WeingartenSTEVEusaPAMikeAmannPC7060
  • MikeAmann
    MikeAmann Member Posts: 990
    edited March 2022
    SuperTech said:


    MikeAmann said:

    Okay then. Good to know.
    So then the ovalized 7" will be the best that I can do.
    No, it won't be as good as 7" round, but it will do the job.
    I am not having the clay tiles smashed out.

    Mike why not have the terracotta removed? If it is already damaged, which in your case is very likely, it's not doing you any favors. With the damaged terracotta removed it will give you more space to install a properly sized and insulated liner. And it will make installing the new liner much easier.  

    I guess a video camera inspection should be the next step.

  • Solid_Fuel_Man
    Solid_Fuel_Man Member Posts: 2,646
    Nahhhhh, once we achieve 100% electrification we won't need no stinken' chimneys! We can use them to shoot fireworks out of! 

    Read this with the utmost of sarcasm!
    Serving Northern Maine HVAC & Controls. I burn wood, it smells good!
    EdTheHeaterMan
  • JakeCK
    JakeCK Member Posts: 1,356
    Nahhhhh, once we achieve 100% electrification we won't need no stinken' chimneys! We can use them to shoot fireworks out of! 

    Read this with the utmost of sarcasm!
    Actually, combined with deep energy retrofits, electrification is 100% a valid means to heat a house affordably. 

    But so many rather buy suburban tanks that cost 50, 60, 70+ thousand dollars every couple years. Yet go for the lowest bidder on anything related to our homes... 

    Of course there are plenty of people who can't afford that, and can't afford those expensive vehicles but when I drive through yuppieville on my way to work there sure are a lot of em'.
    MikeAmann
  • Bob Harper
    Bob Harper Member Posts: 1,030
    Not to worry. In a few years, the UN Global initiative on "Sustainability" will drive everyone to have their homes weatherized, guided by blower door testing, infrared thermography and Duct Blasters. The minimum efficiency for fossil fuel-fired heaters will be condensing. They'll also include energy management systems so you can't control your indoor climate anymore. Electricity will be rationed and you'll have to choose between indoor HVAC vs. charging your car with the $20,000 batteries needing replacement about every 5 yrs and getting stuck on the roadside a lot. This will kill industries that must have petroleum-based fuel such as outdoors, boating, RVs, very quickly. Fuel costs and Green Energy taxes will drive trucking prices through the roof resulting in inflation possibly driving us into a Depression.
    Happy days ahead!
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 7,608
    edited March 2022

    Not to worry. In a few years, the UN Global initiative on "Sustainability" will drive everyone to have their homes weatherized, guided by blower door testing, infrared thermography and Duct Blasters. The minimum efficiency for fossil fuel-fired heaters will be condensing. They'll also include energy management systems so you can't control your indoor climate anymore. Electricity will be rationed and you'll have to choose between indoor HVAC vs. charging your car with the $20,000 batteries needing replacement about every 5 yrs and getting stuck on the roadside a lot. This will kill industries that must have petroleum-based fuel such as outdoors, boating, RVs, very quickly. Fuel costs and Green Energy taxes will drive trucking prices through the roof resulting in inflation possibly driving us into a Depression.
    Happy days ahead!

    Didn't I read a George Orwell book about this in the mid 1980s? Or perhaps my big brother told me about this stuff. I can't be sure. I just remember Ronald Regan's famous quote "I'm from the Government, I'm here to help". And that MUST be true, because it is on the internet now.
    Edward F Young. Retired HVAC ContractorSpecialized in Residential Oil Burner and Hydronics
    Solid_Fuel_ManMikeAmann
  • MikeAmann
    MikeAmann Member Posts: 990
    captainco said:

    What I discovered is that when you have drafthood equipment the flue sizing is based on 50% flue gas and 50% dilution air. This occurs when the draft is -.01" to - .02" When draft exceeds -.02" dilution air is usually increased and takes up room that the flue gases needed. Now a certain percentage of flue gases back up in the equipment. Flue gases are mostly CO2. CO2 is heavier than air and starts blocking the entrance of air into the heat exchanger. Initially because it took a while sometimes for the CO to register on my CO tube, I started to pay more attention to the O2 reading. And sure enough, it would start falling slowly if this was occurring.

    @captainco
    Okay, I am still in this because I want to learn.
    I realize you are talking about draft hoods and gas-fired above.

    My boiler is oil-fired. What you said about the flue gases (CO2) backing up, can that also happen with oil-fired? The reason I ask is that my CO increases (and the O2 decreases) as the boiler gets hotter and hotter. My draft at breech needs to be better. I believe that my baffles are still a little restrictive. The more I increase the firing rate, the worse the numbers go in the wrong direction, mainly the CO ppm increases. And although I have my -.02 over the fire draft, I cannot get the draft in the breach any higher than -.03. When I tried this with one baffle removed (I now have -.03 to -.04 at the breach), I had better combustion analysis numbers.

    SS flue liner will be the first step.
    Step 2 will be dialing in the baffles. I want to keep as much heat in the boiler as possible to heat the water, not wasting it going up the chimney.
    Step 3 will be dialing in the firing rate. Boiler is oversized, resulting in short burner run times. So I want to downfire as much as I can for longer burner run times and to help with the flue gas condensation problem.
  • captainco
    captainco Member Posts: 792
    When fired correctly, the pressure drop of oil equipment is =.02" or =.01 to -.03 or -.02 to =.04. When the pressure drop is less then you are underfired. Notice if you take a draft test when the equipment is not running the draft at the front is the same as the breach. The volume of flue gases create the pressure drop. If the pressure drop is greater than -/02 then you know you have soot build up inside.


    What is your flue temperature and O2 and ?he outlet water temperature. Outlet water temperature plus 245 degrees should be your lowest flue temperature. What is the draft above the barometric when the burner is running and what is the draft immediately after it shuts down?

    I can see where removing the baffle would increase the overfire draft but not the breach. The breach draft is controlled by the barometric and main flue draft. Definitely got me confused on that one or maybe I have to think harder.

    As mentioned before, flue size has little to do with flue gas condensation, unless they are too small.
    MikeAmann
  • Jamie Hall
    Jamie Hall Member Posts: 22,965
    "Actually, combined with deep energy retrofits, electrification is 100% a valid means to heat a house affordably. "

    Well, yes. Perhaps. The authorities are trying that in Scotland as we debate here. They are finding that deep energy retrofits are impractical, when not impossible, in older structures. But -- have to go 100% electric, so they're ripping out -- under penalty of law -- people's fireplaces and chimneys to make sure that they can't heat any other way.

    Problem. Now and then the power goes out. For extended periods. And, folks, people die of the cold. True, mostly old folks and kids out in more rural villages and out in the country, so I guess it doesn't matter, but they're still dead.

    That is, of course, that people can afford the electric rates when the power is on. They've doubled in the last year...
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • JakeCK
    JakeCK Member Posts: 1,356
    edited March 2022
    "Actually, combined with deep energy retrofits, electrification is 100% a valid means to heat a house affordably. " Well, yes. Perhaps. The authorities are trying that in Scotland as we debate here. They are finding that deep energy retrofits are impractical, when not impossible, in older structures. But -- have to go 100% electric, so they're ripping out -- under penalty of law -- people's fireplaces and chimneys to make sure that they can't heat any other way. Problem. Now and then the power goes out. For extended periods. And, folks, people die of the cold. True, mostly old folks and kids out in more rural villages and out in the country, so I guess it doesn't matter, but they're still dead. That is, of course, that people can afford the electric rates when the power is on. They've doubled in the last year...
    I don't know what is going on in Scotland, but if they are forcing people to remove fireplaces and other fuel burning appliances I don't agree with that. However the bottom line is this, while there are plenty of structures that can't be retrofitted, there are plenty more that can be. You don't have to have complete electrification of every structure to meet these goals. Just a large percentage of them, just the ones that can be. 

    One beautiful thing about electricity is that it is incredibly fungible. You can create it from solar, hydro, wind, nuclear, oil, NG, coal... hell you can burn your garbage and generate it. 

    But you can't run your NG boiler off anything other than NG. So what happens when the price of NG skyrockets because of demand or supply? What happens when it is gone? Just because we've gotten better at squeezing out every last bit of toothpaste out of the tube doesn't mean it isn't still going to run out at some point. Sooner or later the oil and gas is going to be gone. So what are we going to do, kick this can down the road another generation? I'd rather start this process now before it's gone.

    And to stay on topic, there is the safety aspect. I've never heard of a heat pump filling a house with CO, killing everyone in it.
    MikeL_2Larry Weingarten
  • ChrisJ
    ChrisJ Member Posts: 15,506
    JakeCK said:
    "Actually, combined with deep energy retrofits, electrification is 100% a valid means to heat a house affordably. " Well, yes. Perhaps. The authorities are trying that in Scotland as we debate here. They are finding that deep energy retrofits are impractical, when not impossible, in older structures. But -- have to go 100% electric, so they're ripping out -- under penalty of law -- people's fireplaces and chimneys to make sure that they can't heat any other way. Problem. Now and then the power goes out. For extended periods. And, folks, people die of the cold. True, mostly old folks and kids out in more rural villages and out in the country, so I guess it doesn't matter, but they're still dead. That is, of course, that people can afford the electric rates when the power is on. They've doubled in the last year...
    I don't know what is going on in Scotland, but if they are forcing people to remove fireplaces and other fuel burning appliances I don't agree with that. However the bottom line is this, while there are plenty of structures that can't be retrofitted, there are plenty more that can be. You don't have to have complete electrification of every structure to meet these goals. Just a large percentage of them, just the ones that can be. 

    One beautiful thing about electricity is that it is incredibly fungible. You can create it from solar, hydro, wind, nuclear, oil, NG, coal... hell you can burn your garbage and generate it. 

    But you can't run your NG boiler off anything other than NG. So what happens when the price of NG skyrockets because of demand or supply? What happens when it is gone? Just because we've gotten better at squeezing out every last bit of toothpaste out of the tube doesn't mean it isn't still going to run out at some point. Sooner or later the oil and gas is going to be gone. So what are we going to do, kick this can down the road another generation? I'd rather start this process now before it's gone.

    And to stay on topic, there is the safety aspect. I've never heard of a heat pump filling a house with CO, killing everyone in it.
    Considering no refrigants are actually safe and many are either toxic, or toxic if burned and or flammable heat pumps can most certainly fill a house with something no one wants to breath.

    Especially with the modern (cough cheap cough) high efficiency evaporators.


    Single pipe quasi-vapor system. Typical operating pressure 0.14 - 0.43 oz. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment
    Solid_Fuel_Man
  • Jamie Hall
    Jamie Hall Member Posts: 22,965
    edited March 2022
    Son, I like your optimism. But you are going to have to force people to go all electric. Some may go along, but a good many won't, because they know that the electricity fails, usually when you need it most. Others may object because they simply can't afford it, or because it is impractical (you can always condemn and bulldoze those buildings though, of course) and others for other reasons. I realise that some folks regard any means, including force, valid if it is justified by the ends. Some folks beg to differ.

    Edit. Sorry for the rant, but there it is. May I suggest, however, that instead of resorting to force, the enlightened ones might spend some time thinking about alternatives? Such as -- just one idea -- adapting existing natural gas infrastructure (which wouldn't help me, but would help many people) to run on hydrogen, and figuring out how to create the hydrogen in a green way? Rathe than forcing everyone onto the electric bandwagon? It would not be difficult -- all the tech. is there -- revised pressure regulating equipment, revised burner flow regulation... I would suggest adding a colourant to the gas (hydrogen burns with a colourless flame, which can be a hazard).
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • MikeL_2
    MikeL_2 Member Posts: 485
    edited March 2022
    captainco said:
     Over 90% of CO poisonings from gas fired furnaces, water heaters and boilers are those with drafthoods performing as designed.
    Captain of CO,
           Can you tell me where to find the study, source, or document that supports this statement so I can add it to the research I'm doing on this subject. 
             I'm interested to know if the draft hood alone failed in some manor, or, if lack of combustion air, competing appliances, blocked or restricted chimney or vent connector,  or some other factors are causing CO poisonings.
              I'm also curious why mechanical engineers, Code authorities, and manufacturers engineers are not doing anything about these type of CO poisonings if draft hoods are so dangerous?
  • captainco
    captainco Member Posts: 792
    Message your email and I will send the 1993 AGA report. If you check the CPSC recall list you will see that the many of recalls have been on drafthood equipment.

    All the equipment tested in this report had draft in excess of -.02" which indicates more than enough combustion air. There were no exhaust fans or competing equipment. Understand
    that this study had to be under AGA guidelines and could not be associated with any other interferences. It does state that we tested under some conditions that did not follow ANSI standards, such as measuring CO continously instead of one reading after 5 minutes and under windy and snowy conditions. The weather conditions were not allowed to be added because the legal department at AGA said their engineer was not a meteorologist and was not qualified. I do believe they accepted that he was a man, even though none of them were biologist!
    DJD775Bob HarperSolid_Fuel_Man
  • MikeAmann
    MikeAmann Member Posts: 990
    edited March 2022
    captainco said:

    When fired correctly, the pressure drop of oil equipment is =.02" or =.01 to -.03 or -.02 to =.04. When the pressure drop is less then you are underfired. Notice if you take a draft test when the equipment is not running the draft at the front is the same as the breach. The volume of flue gases create the pressure drop. If the pressure drop is greater than -/02 then you know you have soot build up inside.

    What is your flue temperature and O2 and ?he outlet water temperature. Outlet water temperature plus 245 degrees should be your lowest flue temperature. What is the draft above the barometric when the burner is running and what is the draft immediately after it shuts down?

    I can see where removing the baffle would increase the overfire draft but not the breach. The breach draft is controlled by the barometric and main flue draft. Definitely got me confused on that one or maybe I have to think harder.

    As mentioned before, flue size has little to do with flue gas condensation, unless they are too small.

    Thank you. I am printing this to use after the new flue liner gets installed. Now I have something to shoot for. Now you've got me thinking. Let's step into my head.....

    For now, I can provide these numbers: (The MagicHeat reclaimer is no longer installed.)
    Burner NOT running draft: both -.02 in the combustion chamber and the breach. I assume this to be good and it means that the chimney is doing it's job?

    Draft at breach WITH burner running: -.025 to -.03 (not solid numbers and depends on outdoor weather conditions). This is where you tell me that I am severely underfired, right? BUT, could my tube baffles be so restrictive that the exhaust can't get out of the combustion chamber fast enough? I seriously doubt it at the firing rate that I am currently running, but the baffles could become a restriction if I increase the firing rate.

    Temp at the breach is now 400F with the water about to reach my HI Limit setting of 205F.
    Outlet water temp plus 245 (205 + 245 = 450). So I am 50 degrees low? Where does this 245 number come from?

    Steamhead posted this back in Nov 2013:
    The flue passages are rather large compared to a modern boiler, but can be baffled to make the hot flue gases wipe the cast-iron better. However, the person installing the baffles MUST make sure they do not kill the draft over the fire, or reduce the stack temperature enough to cause the flue gases to condense.

    The following numbers are from PAST testing when I removed 1 very restrictive baffle, but still using the F0 head which did not allow enough air to pass, so there was smoke of 1.5 with the air bands fully open. (.71 firing rate)
    The draft at the breach was now -.03 with an occasional -.04 and -.02. Removing the baffle worked and proves that I went too far and made them too restrictive. (I could only get -.01 prior.)

    UEi Eagle X C155 measures CO₂ directly & calculates O₂, opposite of a regular combustion analyzer.



    Good numbers, but too much smoke. Removing the baffle did raise the temp at the breach by 100F.




    Next we determined that the burner wouldn't pass enough air to get the smoke down with the F0 head. I changed to an F3 head and now I can achieve ZERO smoke.

    I checked the draft while the boiler was warming up. I have -.03 (2 3 4 on meter) over the fire and -.03 (2 3 4) at the breach. The air band was set at 1.00" open as a starting point looking for a TRACE of smoke. I got a 4. I opened the air band .200" more to 1.200" and got a TRACE. Then I inserted the probe of the analyzer into the breach and got the first column of numbers. The second column is with air added to bring the Co2 down .5% (air band now at 1.558" open). The third column is with the boiler fully hot and about to reach the HI Limit. (.71 firing rate)



    This is with a bigger nozzle - .77 firing rate:

    The numbers are essentially unchanged.
    O2 % same
    CO2 % same
    Efc same
    X air % same
    TF f very close, a little hotter due to the increased firing rate?
    CO ppm slightly higher, again, due to the increased firing rate?

    BTW, here are the best numbers this boiler had from before the rebuild and Flame-Retention head conversion:

    Fall 1997 Wayne Combustion Analysis numbers
    Gross stack 470
    Net stack 400
    CO 10%
    Smoke Zero
    Breach draft -.04%
    Overfire draft -.03%
    Nozzle .85 x 60*A hollow
    Efficiency 82%
    I assume that the angle was narrowed to keep the flame off of the failing walls of the combustion chamber.
    Solid_Fuel_Man
  • captainco
    captainco Member Posts: 792
    If there was a restriction in the heat exchanger the draft over the burner would be lower and possibly positive. With the baffle removed the draft over the burner will be higher and closer to the breach draft, Higher CO when you increase air shows the oil and air aren't mixing as well or you are creating impingement somehow. I rarely have problems getting the O2 down to 4% with zero smoke. It is possible your nozzle is not as good as it should be. For those that are unaware the pattern and the angle of nozzles can be inconsistent. Only the flow rate has to be correct. What nozzle are you using = Hollow, Solid or Semi=Solid. The only one I avoided most of the time was the Hollow. There is no burner today that has an air pattern that matches a hollow nozzle pattern. I really wonder how manufacturers are picking one versus the other. 100% of the oil equipment I helped on or sold with a flame retention burner automatically needed an 80 degree Solid Nozzle, regardless of what was recommended. Remember every oil burner I helped with I was using a digital combustion analyzer measuring O2, CO and Flue temperature. CO at Light off and Shut-down were critical in making certain decisions.

    The 245 degrees adder comes from setting up many oil boilers in the field to their best operation. That is the lowest with plus 345 degrees being the highest.
  • hot_rod
    hot_rod Member Posts: 21,890
    ChrisJ said:
    JakeCK said:
    "Actually, combined with deep energy retrofits, electrification is 100% a valid means to heat a house affordably. " Well, yes. Perhaps. The authorities are trying that in Scotland as we debate here. They are finding that deep energy retrofits are impractical, when not impossible, in older structures. But -- have to go 100% electric, so they're ripping out -- under penalty of law -- people's fireplaces and chimneys to make sure that they can't heat any other way. Problem. Now and then the power goes out. For extended periods. And, folks, people die of the cold. True, mostly old folks and kids out in more rural villages and out in the country, so I guess it doesn't matter, but they're still dead. That is, of course, that people can afford the electric rates when the power is on. They've doubled in the last year...
    I don't know what is going on in Scotland, but if they are forcing people to remove fireplaces and other fuel burning appliances I don't agree with that. However the bottom line is this, while there are plenty of structures that can't be retrofitted, there are plenty more that can be. You don't have to have complete electrification of every structure to meet these goals. Just a large percentage of them, just the ones that can be. 

    One beautiful thing about electricity is that it is incredibly fungible. You can create it from solar, hydro, wind, nuclear, oil, NG, coal... hell you can burn your garbage and generate it. 

    But you can't run your NG boiler off anything other than NG. So what happens when the price of NG skyrockets because of demand or supply? What happens when it is gone? Just because we've gotten better at squeezing out every last bit of toothpaste out of the tube doesn't mean it isn't still going to run out at some point. Sooner or later the oil and gas is going to be gone. So what are we going to do, kick this can down the road another generation? I'd rather start this process now before it's gone.

    And to stay on topic, there is the safety aspect. I've never heard of a heat pump filling a house with CO, killing everyone in it.
    Considering no refrigants are actually safe and many are either toxic, or toxic if burned and or flammable heat pumps can most certainly fill a house with something no one wants to breath.

    Especially with the modern (cough cheap cough) high efficiency evaporators.

    Air to water monoblics have the refrigerant outside. Water or glycol between it and the inside equipment 

    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • MikeL_2
    MikeL_2 Member Posts: 485
    edited March 2022
       Captainco,
              I went through the 1993 study you sent me and I don't see where they confirm or even mention that 90% of CO poisonings are due to gas appliance draft hoods performing as designed? 
              I did see the studies conclusion paragraph that states that barometric dampers out perform draft hoods in some instances, and nowhere in the study did they outline specific operating conditions for residential equipment during the combustion testing........
  • captainco
    captainco Member Posts: 792
    MikeL_2 said:

       Captainco,
              I went through the 1993 study you sent me and I don't see where they confirm or even mention that 90% of CO poisonings are due to gas appliance draft hoods performing as designed? 
              I did see the studies conclusion paragraph that states that barometric dampers out perform draft hoods in some instances, and nowhere in the study did they outline specific operating conditions for residential equipment during the combustion testing........








    If you are the certifying agency that approved all the equipment that we were testing you are not going to self-incriminate yourself. The report is very fluffy. No where does it state that all the equipment tested was producing CO in excess of industry standards nor does it say they were reduced to well within the standards. The way it is stated we could have just reduced the CO from 10 ppm to 9 ppm, but that was not the case. Also there was no part of the study that we were assessing the efficiency of the equipment unless he meant it was burning more complete. The engineer that did the study with us was the one that told me off the record that drafthoods were the most dangerous device ever invented. He was also given a gag order and was not allowed to go back into the field. The test results did not make the management at AGA very happy!
    As far as the 90% of CO poisonings caused by drafthood equipment is based on my experience and research following 1000's CO poisoning for over 35 years. Because none of my field experiences were funded by the government they don't count. I could list all of the CO poisonings that have occurred in the last years from gas fired equipment and you would see they were almost all drafthood equipment. Just Google CO poisonings and see what equipment is on the job. Most of the time it is reported there was a CO leak. I guess when there is a gap between the equipment and the flue there is a pretty big leak!

    A drafthood totally eliminates the possibility of controlling combustion air to the burners. Draft controls combustion air but if you are isolated from the flue which contains the draft that cannot happen. Have you ever seen a Code or instruction that requires combustion air to be controlled or verified?

    As I mention earlier, Google Jim Davis Combustion or Carbon Monoxide and read the comments of many of our students. I have not invented or created anything. I have just measured and observed and now do my best to share and educate all those that want to learn what I have experienced.
  • MikeL_2
    MikeL_2 Member Posts: 485
         I guess I am naive, Captainco. I would expect an engineer to adhere to a professional code of ethics when safety & liability issues are identified,  regardless of the cost.
         
  • MikeAmann
    MikeAmann Member Posts: 990
    captainco said:

    If there was a restriction in the heat exchanger the draft over the burner would be lower and possibly positive. With the baffle removed the draft over the burner will be higher and closer to the breach draft, Higher CO when you increase air shows the oil and air aren't mixing as well or you are creating impingement somehow. I rarely have problems getting the O2 down to 4% with zero smoke. It is possible your nozzle is not as good as it should be. For those that are unaware the pattern and the angle of nozzles can be inconsistent. Only the flow rate has to be correct. What nozzle are you using = Hollow, Solid or Semi=Solid. The only one I avoided most of the time was the Hollow. There is no burner today that has an air pattern that matches a hollow nozzle pattern. I really wonder how manufacturers are picking one versus the other. 100% of the oil equipment I helped on or sold with a flame retention burner automatically needed an 80 degree Solid Nozzle, regardless of what was recommended. Remember every oil burner I helped with I was using a digital combustion analyzer measuring O2, CO and Flue temperature. CO at Light off and Shut-down were critical in making certain decisions.

    The 245 degrees adder comes from setting up many oil boilers in the field to their best operation. That is the lowest with plus 345 degrees being the highest.

    This is great info. Thank you. It will certainly help dialing the burner after the SS liner gets installed.

  • captainco
    captainco Member Posts: 792
    MikeL_2 said:

         I guess I am naive, Captainco. I would expect an engineer to adhere to a professional code of ethics when safety & liability issues are identified,  regardless of the cost.
         

    What engineer do you know that has spent years in the field doing combustion testing? Even the ANSI standard states that inherently all gas equipment is unsafe but to make them totally safe would prevent their operation. How may times have you talked to an engineer in the field to solve a service problem? How many makes of equipment designed by engineers gets recalled because of defects?
    Engineers all have high IQ"s and a lot of book learning. They are all smarter than me or us but they have very little real world experience. Show me a book, or manual on combustion diagnostics that are used in college engineer courses. No such thing!
    You are not necessarily naive, just not aware of all the real truths. But if you keep asking I will keep trying! Maybe I will send you a few more tidbits of info.
    MikeAmann
  • MikeL_2
    MikeL_2 Member Posts: 485
    captainco said:



    In 1992 I participated in a field study with AGA Lab on the operation of drafthood equipment in the field. 18 different pieces of equipment with drafthoods were tested in December in Northern Ohio. 18 out of 18 tested unsafe!!  Their engineer was given a gag order and not allowed to test in the field anymore. He had to quit his job and found another one. AGA stopped certifying gas equipment in 1994. Off the record I was told drafthoods are one of the most dangerous devices ever invented. 
            This is the engineer I was referring to. 
  • Bob Harper
    Bob Harper Member Posts: 1,030
    Codes and standards do not guarantee performance and can, in some cases, harm or kill. I sit on code committees for venting stds. Change is slow and politics do play. Also, I've never met an appliance that can read to know how its expected to behave. That's why we test and why there will always be the dichotomy between compliance vs. function. Sometimes that means if you don't convert a draft hood to a baro. damper or adjust manifold pressure above spec, it will be hazardous. Techs are forced to make choices all the time: follow the rules and pray no one gets hurt or do what you have to within your training knowing no one has been documented injured or lost property doing these measures.
    STEVEusaPAcaptaincoMikeAmannSuperTech
  • Solid_Fuel_Man
    Solid_Fuel_Man Member Posts: 2,646
    I'm just thinking of the Many many many propane water heaters I've when I was a kid sitting in the corner of the basement with NO flue connection at all. You could tell by the heaviness in the air. 

    However no one died, was it healthy? Of course not! My point is that most houses are leaky as a sieve, even new ones. 

    I was in a home two years ago with one still firing away like that. 40+ years old, piped up with 1/2" soft copper the whole way from the 2 stage regulator 50' away. Everything wrong with that installation, but it had worked for at least 40 years.....

    I did tell the homeowner that is was not good or safe, and you know what the response was.....40 years.....
    Serving Northern Maine HVAC & Controls. I burn wood, it smells good!
  • ChrisJ
    ChrisJ Member Posts: 15,506

    I'm just thinking of the Many many many propane water heaters I've when I was a kid sitting in the corner of the basement with NO flue connection at all. You could tell by the heaviness in the air. 

    However no one died, was it healthy? Of course not! My point is that most houses are leaky as a sieve, even new ones. 

    I was in a home two years ago with one still firing away like that. 40+ years old, piped up with 1/2" soft copper the whole way from the 2 stage regulator 50' away. Everything wrong with that installation, but it had worked for at least 40 years.....

    I did tell the homeowner that is was not good or safe, and you know what the response was.....40 years.....


    What do you expect the response to be?

    Kitchen stoves do not require any kind of venting.
    Single pipe quasi-vapor system. Typical operating pressure 0.14 - 0.43 oz. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment
  • MikeL_2
    MikeL_2 Member Posts: 485
    edited March 2022
    Captainco said,








    Have you ever seen a Code or instruction that requires combustion air to be controlled or verified? 
          Yes, all of the equipment I install include specific guidelines regarding combustion air in their installation manuals, and, some manuals include information on how to calculate combustion air available indoors and how to correctly introduce outdoor air if needed
    ......
  • captainco
    captainco Member Posts: 792
    MikeL_2 said:


    Captainco said,








    Have you ever seen a Code or instruction that requires combustion air to be controlled or verified? 

          Yes, all of the equipment I install include specific guidelines regarding combustion air in their installation manuals, and, some manuals include information on how to calculate combustion air available indoors and how to correctly introduce outdoor air if needed
    ......

    That is the same combustion air that ASHRAE did a study and said it doesn't work under many conditions in the field and that Code does not allow for professional designed systems. They stated that only mechanical combustion performs under all field conditions. But even then, combustion air that is working doesn't confirm equipment venting. The Code still says to use a match or smoke to verify drafthood equipment is venting and yet it only verifies room air is venting. Measuring draft does verify if there is plenty of combustion air going to the equipment but even then it does not verify venting. Only a combustion analyzer can do that 100% of the time.

    Combustion air openings to an attic suck air out of building 100% of the time, but it is in the installation manuals. Combustion air out the roof sucks out almost 80% of the time. Furnaces installed in closets with louvered doors rarely performs correctly. Holes in the wall suck out as often as they suck in. These are all in manufacturers instructions regardless.

    All equipment has been tested in a room that was positive pressure. Code approved combustion air requires the room to go negative in order to bring air in. If you have never seen a furnace, boiler or water heater without rust then I guess you have never had a combustion air problem.

    One of NCI protocols and even some national protocols require a depressurization test to verify adequate combustion air. The difference between NCI's test versus other tests is we verify if it affects the equipment operation not just the room.

    Sometimes when you respond or try to get into certain websites there will be sometimes you will have to do that says you are not a robot. We believe at NCI that everyone has a brain and it is there greatest tool! But you have to use it!

    I believe you and everyone on here have much more talent than I do. However when it comes to combustion equipment performance I have very few challengers. I often say in class that this is not a complement, just a bad state of affairs.
    Bob Harper