Cracked Heat Exchanger

[Russel Ray]

Originally Posted by jrupert

2). Furnaces that are operating normally will produce Carbon Dioxide, when combustion is effected so it is not burning properly they it can produce Carbon Monoxide. A furnace with a crack may burn clean and not produce C02, but it still must be replaced.

If you dig down deep into the chemistry of burning organic fuels, I believe you'll find that both carbon monoxide and carbon dioxide are produced as byproducts during any burn that is not 100% efficient. And nothing that we use in our homes is 100% efficient. Carbon monoxide also reacts with oxygen and/or moisture (H20) in the air to produce carbon dioxide.

It is dangerous for anyone to state that carbon monoxide is not produced by burning organic fuels. Just do a Google and a little reading; there's enough information out there to convince most people to go electric.

[Russel Ray]

Here's just one reference that is out there on the Internet:

http://www.chemheritage.org/EducationalServices/webquest/tg/power.htm

Chemical Reactions and Reaction Products
An understanding of chemical reactions and reaction products is important to this activity. Several of the questions deal with the production or burning of fuels. In both cases, chemical reactions and reaction products are involved. In the burning of fuels, the fuel reacts with oxygen, and the resulting products are of great importance as they may be benign (like water from burning hydrogen) or they may be hazardous (like carbon monoxide from burning organic fuels). This result must be taken into account when considering alternative fuels. The production of fuels also involves chemical reactions and their products. There are several methods of producing hydrogen, a potential fuel for both fuel cells and internal combustion engines. While the use of hydrogen as fuel produces only water as a reaction product, not all methods of hydrogen production are so harmless. Hydrogen can be produced by the electrolysis of water, essentially the reverse process of that which acts in fuel cells. However, methods that produce hydrogen by breaking down hydrocarbons also are being proposed for large-scale production. These processes produce carbon dioxide as a waste product, which is a greenhouse gas. Clearly, understanding reactions and reaction products is central to sorting out the issues involved in the quest for long-term energy solutions.

[Russel Ray]

Organic fuels are carbon based (the C). Carbon (the C) is the sixth most abundant element in the universe, being in many different compounds, such as food, clothes, cosmetics, and, of course, fuel. It has a melting point of 6422°F and a boiling point of 6917°F. So when burning organic fuels, carbon will be produced since it’s not going to be burned because nothing we do outside of a laboratory, a huge fire, or a nuclear reactor will be hot enough to burn the carbon. And yet carbon is used as control rods in nuclear reactors, as well as added to clays to form the “lead” in pencils, added to iron to make steel, etc.

Most (if not all) of our fuels are in the methane family, which are various combinations of carbon and hydrogen (methane - CH4, ethane - C2H6, propane - C3H8, butane - C4H10, etc.). In burning them, combine the fuel with oxygen and one gets a very powerful reaction (think the Zeppelin, which was full of hydrogen gas). In a complete burn (100% efficiency) two oxygen atoms will combine with the one carbon atom to produce carbon dioxide (CO2) and water (H2O). Incomplete combustion (anything less than 100%, even 99.99%), will produce trace amounts of carbon monoxide (CO) as well as carbon dioxide and water. You’d have to write the chemical equation to see how this works in a simple case, and then balance that equation to see how complex it can be depending on the efficiency of the burn.

The most important fact, however, is to always remember that burning organic fuels—in other words, burning anything in our homes—produces carbon monoxide. With appropriate ventilation, knowledge, and caution, it rarely becomes a problem. However, a quick read of the daily news at
http://www.bacharach-inc.com/co_news.htm
will show you just how dangerous carbon monoxide is.

[jrupert]

I apologize that you misunderstood my statement, I did not mean to suggest that furnaces can burn clean or 100% efficient, all heating appliances do have a byproduct of combustion, nor did I mean to suggest that carbon monoxide is not present in some level on a properly working furnace.

What I meant is that as long as the measured levels of CO are within the published norms then all is ok. A working furnaces produces primary carbon dioxide.

See these two good references

http://www.bpi.org/bpi/www/uploads/pdf_88829PM_4.pdf



http://www.karg.com/CO%20Protocol.htm

[Russel Ray]

Both references simply reinforce what I posted.

Oxygen is needed for combustion, and when there is not enough oxygen to combine with the carbon to produce carbon dioxide (CO2; carbon and two oxygens), then one gets carbon monoxide (CO; carbon and only one oxygen). One can never fully get rid of carbon monoxide emissions when burning organic fuels because nothing we have is 100% efficient, but one can reduce carbon monoxide emissions to very, very low levels, all things considered.

The fact that burning organic fuels produces carbon monoxide as a byproduct, even if at every low levels, is why the gas company, and my company, recommend the installation of carbon monoxide detectors in all residences, particularly those with gas-burning appliances and fireplaces, and an annual inspection/servicing of those same gas-burning appliances and fireplaces. Unfortunately, rarely is that done, which is why the news at
www.bacharach-inc.com/co_news.htm
goes on and on and on.

[Dean Call]

Originally Posted by rray

That's a dangerous statement, even with the "IF."

Anything that burns organic fuel (such as wood, oil, gas, etc.) will produce carbon monoxide because it is a natural byproduct of the burning process. The only time that carbon monoxide would not be produced is if a system were 100% efficient. And 100% efficiency doesn't exist on this earth outside of a laboratory, and I'm not sure that it exists in a laboratory either.

I think a Google search and a day's worth of reading is in order.

Not really true (as in anything that burns always produces Carbon Monoxide). But it is true that anything that burns CAN produce Carbon Monoxide.

My bad, I should have specified "gas furnace" because those are the ones that I know about and don't know about wood, oil, coal or any other fuel mentioned.
Efficience has nothing to do with it, an older 60% efficient gas furnaces can have and do have complete conbustion and complete combustion = CO 2
I do know for a fact from experience a good clean burning gas furnace does not produce Carbon Monoxide unless something is wrong with it.

I have been checking every furnance I've serviced for many years now and anytime I find Carbon Monoxide readings within the flue or draft hood or in or around the furnace I find out why and repair it or shut it down.

That is in no way to say I'm making light of a cracked heat exchanger at all. When I find a cracked heat exchanger I always shut the furnace down imediatly, producing Carbon Monoxide or not, many are not but the potential is still there.

I've had homeowners relite and turn the furnace back on after I left and probably even called me a crook for fullfilling my obligation by shutting down their furnace but a least I can sleep at night knowing I did my part.

We file our customers by addresses (as well as by name and by phone number) and I've gone back a year or two later when the house had a new owner expecting to find a new furnace since I had been there and I see the previously history on our computer before going and found the same old furnace with the same cracked heat exchanger that I had shut down previously, now back in operation.
That's usually when the new home buyer starts getting on the phone to the realtor about failure of disclosure.

I only tell that story to demonstrate that a cracked heat exchanger doesn't necessarily always mean Carbon Monoxide.
Maybe I shouldn't have even mentioned it since it's relly a moot point anyway and besides I can't say that the people living in the house haven't been having too many headachs.

Again though, I think everyone knows a cracked heat exchanger certainly does mean danger and the furnace should be shut down ASAP even though it might be burning perfect at the time.

[Russel Ray]

Originally Posted by Dean Call

Not really true (as in anything that burns always produces Carbon Monoxide). But it is true that anything that burns CAN produce Carbon Monoxide.

You'll find a world full of chemists, including this one, who will disagree vehemently with you, and they have the chemistry theory and experimental data to back up their words.

Anything that burns and that is not 100% efficient in burning everything will, indeed, produce carbon monoxide (CO). That's important to know because CO is dangerous. So once we acknowledge that fact, which, for some reason, you seem to be unable to do, we can continue to work on the burning process to control the amount of CO that is produced, either during the burn or after the burn.

Since incomplete combustion results from the lack of oxygen--ya just gotta have that oxygen to make the burn go--there won't be enough oxygen molecules to attach to the carbon atom. Carbon naturally wants to make love with two oxygen atoms (carbon dioxide; CO2), so if there ain't enough oxygen atoms (incomplete combustion), one will, indeed, get carbon monoxide (CO).

We could always hook up the furnace to an oxygen bottle; that might work. However, that would also be prohibitively expensive, especially since we can get oxygen free from the air around us. The mere fact that the air around us simply doesn't provide enough oxygen molecules to burn anything 100% means that CO will be produced.


So one can solve the problem by continuing to add oxygen, even after the burn, so that, ultimately, the CO can get that second oxygen atom that it's looking for. However, that is exactly the reason why CO is so dangerous. Notwithstanding the fact that CO is odorless, colorless, and tasteless, the best place to get that second oxygen atom is your lungs as you breathe. You have oxygen in your blood, and that CO as you breathe it in will attach to those oxygen molecules, basically strangling you from lack of oxygen. Once all the oxygen in your blood has decided to create a love triangle with the CO couple, there is no more free oxygen in your blood and, yep, you guessed it, you're dead.

Stating that properly operating furnaces don't produce carbon monoxide is a dangerous, perhaps even irresponsible, statement. Stating that a properly operating furnace controls the amount of carbon monoxide emitted/detectable is a much better statement.

[Dean Call]

Well I'm sure in the name of safety it's best that everyone does believe that all furnaces do produce CO even though it's really MOSTLY CO2 so I won't keep arguing the point after this.

I think because I don't count 4-6 ppm as is actually producing CO is where the difference probably lies.

What I think is humourous is for someone not in the industry to try to make me believe that all my expensive CO detectors I've had in the last 41 years were wrong when they show readings too low to even show any ppm when the readings were taken directly inside the flue pipes.
Also I have been in many houses where there was NO flue pipe at all connected with all the flue products dumping into the house and there were NO side effects.
In fact most of the times the people weren't even aware of the fact.
Only a small percentage of the folks intentionally connected a gas heater and left off the flue pipe.

When I've tried to explain how dangerious the situation is and how Carbon Monoxide is a deadly poisonous orderless gas, some have said "my gas oven doesn't have an exhaust pipe so what's the difference" Or "how come were not dead then, it's been that way for ...?"

Anyway, you are right 3-4 ppm IS Carbon Monoxide so I won't say anymore.

[Russel Ray]

Originally Posted by Dean Call

I think because I don't count 4-6 ppm as is actually producing CO is where the difference probably lies.

Perhaps. And that's where the danger comes in, as well. The sick, the elderly, the newborn, and others can be affected greatly by low carbon monoxide levels, especially over the long term. Carbon monoxide is not something to take lightly or dismiss summarily.

Originally Posted by Dean Call

What I think is humourous is for someone not in the industry

You make some bold presumptions. That, also, can be dangerous. Nonetheless, one does not need to be in the heating industry in order to understand carbon monoxide. In fact, unknowing people in the heating industry might do a greater disservice to that industry than someone outside the industry who understands carbon monoxide. Chemists also probably have a good understanding of carbon monoxide, how it is produced, and its effects. And a chemist with experience in the heating industry has two things going for him over some unknowing person.

Originally Posted by Dean Call

When I've tried to explain how dangerious the situation is and how Carbon Monoxide is a deadly poisonous orderless gas, some have said "my gas oven doesn't have an exhaust pipe so what's the difference" Or "how come were not dead then, it's been that way for ...?"

Hopefully you were able to explain it to them intelligently, which you have not done here.

[William Warner]

I'm by no means an expert, but from my chemistry classes in college and (dare I say) high school, complete combustion can only be achieved in OPTIMUM conditions. Unless in a laboratory setting... where there's flame, there's INCOMPLETE combustion and thus Carbon Monoxide regardless of the levels.

From Biology classes... CO attaches to red blood cells (hemoglobin to be exact) much easier and more efficiently than Oxygen does, and when attached will actually prevent Oxygen from attaching, and stays attached longer...hence the health hazards... you are effectively suffocating without the choking sensation. It will take higher levels to affect a healthy adult, but children and elderly are at greatest risk. Without a CO detector installed in the home, one is playing Russian Roulette. It happened in this area at least 5 times this heating season, 3 of them from faulty heating sources. When you begin to feel the effects, it can often be too late.

It's been that way for years...

I just love that one Tell that to the families who lost loved ones this season. Their heating sources were that way for years as well. And their Dad ran that generator in the garage like that for years also.

If it's been that way for years then you're either ignorant or love to gamble with your lives.

I'm with Russel on this. It may have low levels or non-measurable levels of CO today, but what about tomorrow or the next day, or next year? I will always recommend a CO dector with ANY fuel burning appliance in the home. Even if it is top of the line and installed as I was inspecting. I'll let someone else put a gaurantee that complete combustion is taking place 100% of the time.

An excellent site that explains this about indoor air quality and physiology of CO in the blood stream http://www.nutramed.com/environment/monoxide.htm

[lfoster]

Originally Posted by bkelly1

Here are a couple I found in the last couple of weeks.

Looking at the previous 2 pics, I don't see the cracks. Please point out where to look .

[tnoisaw]

One my second day on the job as a plumbing apprentice I went to a call with my boss on a furnace. The heat exchanger was cracked and the home owners were hospitalized for a week luckily with full recovery. The CO2 reading was way off the charts.