Whoever said oil burners can't produce CO

Steamhead

is dead wrong................



<a href="http://baltimore.cbslocal.com/2011/05/16/co-poisoning-to-blame-for-couples-death/">http://baltimore.cbslocal.com/2011/05/16/co-poisoning-to-blame-for-couples-death/</a>

Jean-David Beyer

Whoever said oil burners can't produce CO

Not only dead wrong, but

making a grave mistake.



Did anyone really say anything as dumb as that?

If you burn hydrogen in oxygen, you get no CO because there is no carbon. But most fuels do contain carbon, so they can result in carbon monoxide. I suppose everyone here already knows this.



I was just hinking of things that can burn in oxygen and produce no CO.



Hydrogen, magnesium,  .. a lot of the tings in the first two columns of the periodic table. Some of them result in hazardous byproducts, and I would not want to have to design a boiler burning powdered magnesium.

Tim McElwain

The concern with oil personal

is that they have been led to believe over the years that "Zero" smoke means no CO "NOT TRUE NEVER WAS"!



The other problem with oil service personnel is that for years when they only tested with a "wet kit" they only tested CO2, they never tested for O2, they did a smoke test and then a stack thermometer gave them flue gas temperature. They then went to a "Fire Finder calculator" to come up with efficiency. The failure to test for O2 meant that CO2 could have been on the wrong side of the combustion curve (making CO) and they would never know it. They never used a CO ampule to at least see if there was some discoloration indicating the presence of CO.



The same fallacy often existed with gas testing in that "if the flame is blue it is not making CO". This is not true and never was. At least gas service personnel tested with wet kits CO2, O2 and CO along with stack temp. We also used a "Fire Finder" to determine efficiency.

Charles Johnson

Wrong side of combustion curve?

Tim, what do you mean exactly by the wrong side of the combustion curve?



I assume you mean if your gas air mixture gets rich to the point where you have zero O2 and you remove air or add fuel the O2 starts to go back up and CO2 back down.  Of course I could be wrong and would appreciate if you would correct me.  I have not yet expeienced this scenario.



And just for the record I have seen oil burners producing dangerous CO levels with zero smoke, so I agree, whoever said it can't happen is a very dangerous person to listen to!

Tim McElwain

Right and wrong side of the curve

on the right side of the curve for gas when O2 goes up CO2 comes down. At around 9.5% CO2 a gas flame can be a real steady soft blue flame and look good by eye. To insure we are not on the wrong side of the curve we will increase O2 if we are on the wrong side and reading originally 9.5% the reading will go up instead of down this is how you know you are on the wrong side and you will also have very high CO. If you did not take and O2 reading and a CO and went strictly by the flame then you could be fooled. I have a combustion efficiency chart I use to chart all my readings to see what side I am on.

Mark Eatherton

Charles...

click on this link and scroll down to see a graphic example of the theoretical combustion curve.



http://www.analyticexpert.com/2011/01/the-combustion-geek-part-three/



ME

Jim Davis_3

Oil CO

For years the oil industry stated oil doesn't make CO and if it did there would be so much smoke you wouldn't need a CO detector.  They have been wrong since day one.  My first exposure to CO and oil was in 1984 testing a 90%+ oil furnace.  Zero smoke and 5000+ppm of CO.

I am not sure how many have ever been on the fuel rich side of the combustion curve but if you have then you would know that O2 exists on that side and the richer you get the higher the O2 gets. I have only seen it on industrial applications on process equipment.  Bercause I had CO analyzers that went as high as 100,000ppm I was able to tell the difference.  Watching the O2 reading drop as you decrease fuel input was initially quite confusing and didn't make sense, but I knew I was going in the right direction.  But then the O2 dropped to zero and started rising again as I got to the excess air side of the curve.  Therefore neither O2 or CO2 can tell you which side of the curve you are on, only CO and smoke can.  Of course they exist on both sides of the combustion curve also. 

Steamhead

Those of us who have Firedragon's books

know this as the "Lanthier Scale". But whatever the term, the principle is the same.



Note to homeowners: Firedragon (George Lanthier) only sells his books to those in the business. But you might ask someone working on your system if he/she has them. George is one of the best in the business, like Tim, so someone who has trained with him SHOULD be fairly capable...........

NH03865

Firedragon's books

I just visited Firedragon's web site and found that anyone can purchase his books.

This is from the store policies page





Books and tools may be purchased by anyone, however, we are not a service house or 'do-it-yourself' helper and we make no warranty or assume any liability for misuse or improper use of the information contained within the books and for any product we sell.

Steamhead

That's a recent change, then

in the past he has not sold to the public. 

turtle12

High CO readings

Hi



I do energy audits and have been getting CO levels over 100ppm in oil fired residential furnaces and boilers. Some contractors working with me have been getting 2-4 ppm in the same boiler. I'm using a Bacherach. They are using Testo. We tested side by side. Any thoughts??

Steamhead

Maybe

someone has a bad CO sensor? 

Tim McElwain

The answer is

Bacharach does not eliminate nitrous oxide with their CO readings. Testo has a NOX eliminator in their meter so your air free reading will be much lower on the Testo than on Bacharach. There is nothing wrong with the meters!

Jim Davis_3

NOX filtered

I agree that the Bacharach will always read higher than the Testo but usually only 20-30ppm not 80ppm to 100ppm.  Sounds like a calibration issue.  After a couple of years CO sensors can drift higher or lower. 

billtwocase

I think

it was more of not knowing or ignoring the warning signs that you get from an oil fired unit. With a house full of haze that you can cut with a knife, sounds like a blocked chimney, improperly wired power vent, or whatever vents the system. I think there is a misconception here, but more of oil gives you much more warning signs than a gas appliance and not that oil produces no CO. To think that all oil guys have that mentality is not a good thread to post. We are considered stupid and cheap in another thread, now we are potential murderers? What wrong turns are these boards taking?  Just my 2 cents

lchmb

Bill

I to, would be curious to see the outcome of this investigation.

billtwocase

This is a very sad and unfortunate case

If the smoke pipe rotted off and the unit has been venting in the home for some time, all those combustion results can be thrown into the wind. Without a proper negative draft, the combustion will not be as tested if tested. If someone just serviced it, then throw then all bets are off. If there is a follow up to that news, I'd also like to know. Where does high CO go when it is vented properly?

Steamhead

If it's vented properly

of course it goes outside. This is one reason some people aren't concerned with CO levels in flue gases.



But what if the chimney gets blocked? Read this one, from the previous incarnation of The Wall:



http://www.heatinghelp.com/forum-thread/113623/Check-em-ALL-Steamhead



Tim's comment (shows up as posted by N/A) in that thread means a lot to me.

billtwocase

no doubt

levels should NEVER be that high vented or not. I think we can all agree on that. If this unit was just checked/serviced/tested with high CO readings, then someone will soon get some well deserved punishment for the tragedy. Unfortunate that no one looked in on these elderly people, and discovered that something wasn't right, and to have those levels of CO in the house, it was not a short term issue.Either way our thoughts and prayers go out to them

meplumber

bill and I have had this discussion before.

It isn't that the oil techs don't think that oil can produce CO. It is that by the time there is a problem with the equipment, there is usually such an oil odor in the house that it is noticeable.



I have been in houses with oil furnaces with problems, where there was a black film on the walls near the registers. However a calibrated CO meter was only reading between 30 - 50 ppm. Now I know those numbers are above allowances, but the smell of oil combustion shows itself pretty quickly.



CO is a concern anytime you burn a fossil fuel. The fall back for oil techs has always been that you will smell a problem pretty quickly.



Great discussion by the way.

Mark Eatherton

Even the BEST appliance under IDEAL conditions will produce CO...

under the "right" conditions. Think about it.



You tested the burner (pick your fuel of choice) and have the appliance running in a "Stoichiometric" condition. Everything is PERFECT. (I've seen this 2 times in my 35 years of testing)



Now, introduce a variable (draft or expulsion of flue gas products due to vent disconnection) and you have a deadly situation.



What is the primary byproduct of combustion? CO2.



Can a flame be sustained in the presence if CO2? NO!



What causes the production of Carbon Monoxide? Incomplete combustion.



What WILL cause the production of CO in an otherwise "PERFECT" combustion process? The introduction of CO2 into the incoming combustion air. Obviously, we are talking non sealed combustion appliances here...



If an appliance has high CO in the flue gas stream, will this compound problems if flue gas spillage occurs? ABSOLUTELY. If it is in the stream, all it takes is a wind from the right (wrong) direction, or a negative pressure from a newly installed device (Jenn-Aire Grill) and suddenly, the CO is no longer contained in the flue pipe...



A disconnected vent is a guaranteed way to generate CO with a perfectly set up appliance. A spilling vent is going to provide the same conditions. In many cases, with an electronic non lock out system, the oxygen levels eventually get so depleted that the appliance can't fire. Once it goes into soft reset lock out, the O2 levels come back up to the point that combustion is once again allowed, until it self snuffs again. This is why I think that ALL ignition modules should be a 100% lock out.



Appliances with a standing pilot will self snuff, and won't relight, causing the consumer to place a cold call to their service company, or causing them to relight their pilot without checking for venting anomalies. Regular pilot outages should be a big indication of potentially deadly problems, but in most cases ends up turning into a pilot adjustment, and thermocouple replacement.



We as an industry have a lot more education to do...



If, God forbid, someone gets sick or dies, and it becomes a legal case, the jury will hold your feet to the fire. Pleading ignorance is not a good option.



Remain vigilant. TEST, TEST, TEST, and install every safety device (spill switches, 100% lockout ignition modules) possible.



ME