altering burners, lowering CO?

jp_2

I have a question for mark E and I guess jim davis and crew.

from marks post:

(((I thought back to what you'd taught me, closed my eyes, opened my mind, and looked in the combusion chamber and found the flames impinging on the cast iron sections. Lowered the manifold down to 2-1/2 inches and dropped the CO to 20 PPM.)))

when you do this, aren't you lowering the efficiency of the boiler? when i raise the coffee pot off the burner it takes longer to make coffee.

this has nothing to do with dangers of CO, so don't harp on that side of the subject, please!
I also do not want to agrue about what the manufacturer says about altering equipment, this is just as simple as the question. no hidden agenda.


mark, i would have posted this in the thread where it came but thought likely you would not return there.

also:
(((I was a little woosey from the background 35 PPM Co in the mechancial room..)))

don't you want to investigate this 35ppm open room CO, where was this coming from? I'm assuming the thing was venting properly, may be not?

Mark Eatherton1

No problem...

JP, I intentionally didn't get involved in the other thread because I do NOT consider myself as the ultiamte expert in regards to CO. Jim Davis and Timmy Mc are my mentors. I knew that the thread would play itself out and information disseminated and the dust would settle. A few barbs were slung, and for tht I feel badly, but thats likely to happen in ANY discourse of a spirited nature. Kudos to you for attempting to make ammends. That's the Wallie way.

The fact is, this was in older 3 section modular boiler, made by HydroTherm. One of the boilers was leaking water into the combustion chamber, so we disabled it and didn't bother to pull and clean its burner.

CO from a dirty burner comes from many reasons. Sometimes as simple as dust in suspension, or dust picked up off the face of the burner and fouled combustion, and CO production. The boiler was 40 years old, and other than repairative maintenance, had never really been serviced. My first thought was, "Pull the burners and clean them up and go forward from there". We did, and we still had a probelm. Next step, check for proper and adequate draft at the outlet of the appliance, and inlet to the chimney. No problem, a steady -.05" WC draft downstream of the draft hood, and a constant -.02 draft at the appliance breaching.

Next step, diagnose fuel input. This is where I discovered the gas pressure being twice as much as it should have been. Made adjustemnts to "industry standard" for an atmospheric appliance input (per the lable on the boiler) and the CO was STILL way too high. This is where most people would have thrown their hands into the air and told the consumer they couldn't fix it because the appliance was within "normal specs". This is also what seperates the men from the boys. I took the bull by the horn, made adjustments out of "normal specifications" and got the CO down to a reasonable level. I could actualy see the flame contacting the cast iron section of the heat exchanger. As soon as I backed the pressure off and got the flame away from the cast iron, the CO dropped like a rock.

Am I concerned as a contractor for taking an appliance out of "normal operating parameters"? Not nearly as worried as I'd be if I left it in the condition I found it in and it had killed someone. All the manufacturer has to say is that it was out of warranty, and their liability pretty much ends there unless it can be proven beyond a reasonable doubt that it was a defective design, which would be pretty hard to do for a 40 year old appliance.

Do you think the manufacturer would come stand by my side in court and say that my leaving it within normal operating parameters was OK even though it was still exceeding industry accepted CO standards? Not on your life.

CO is something to be treated with great respect. It can kill and maim for life. This is another one of those "real world" applications where the manufacturers get shivers down their back. "It didn't do that in our laboratory..." but then again, thier labs are operating under perfect conditions.

As an example, theres an industry standard for testing roll out switching devices located at the burner inlet to the appliance. The manufacturer is required to block flue passages one by one until the roll out switch deactivates the burner. I don't remember the exact parameters, but I can tell you this, it's GARBAGE. I've seen more plugged up rolling out boilers that had roll out switcheds on them that didn't EVEN actuate when they should have and people were ill because of it. The manufacturers do the minimum required to get thier appliances approved under the GAMA, AGA, CGA requirements. If they were REALLY serious about stopping CO deaths, they'd have a fusible link that ran the FULL width of the burner tray to detect ANY roll out that was occuring, but NO... that would cost more money, and the people at the top running the company don't want to spend that kind of money. It would cause their products to cost more...

Back to your original question on boiler eficiency, and I know I'm going to upset the apple cart with this statement. It has been my personal experience that cast iron, and steel boilers true thermal efficiencies, and their "stated" efficiencies are two completely different worlds.

I've challenged the industry to state thier "true thermal efficiencies" before, and the only ones to respond are the tankless wall hung boiler people. They UNDERSTAND net thermal efficiency. That's what drives their sales. They can't make claims without proving it.

A.F.U.E. is garbage as well, and the industry knows it.

Show me the numbers. I put in this much energy, and I take out this much energy. The net thermal efficiency is the true output divided by the true input. Simple as all that.

I've seen my own little T-50 condensing boiler at 99.5% true thermal efficiency NUMEROUS times under differing conditions, and it WASN'T at full burn. My "lab" is not your typical home set up. I've got calibrated metering devices all over my system and can tell you to the minute what the true net thermal efficiency is.

Two other things to ignore are the "combustion efficiency" number produced by combustion analyzers and thoeretical heat loss calculations. Neither one survives the real world test. Am I saying that you don't need to do a heat loss calculation? NO. What I'm saying, is that even under "ideal conditions", where I know for a fact that the heat loss calcs WERE done, and the properly sized equipment was installed and propelry adjusted, when I show up and it's been design conditons outside for 24 hours, and the boiler is cycling off and on to the tune of a 50% duty cycle, it throws the theory right out the door. And before anyone jumps to conclusions about solar gain, body gain and internal gains, it WAS taken into consideration. THere are many things that our loss clacs don't take into consideration that have a SUBSTANTIAL influence on the operation of the physical plant, like the Thermal Mass Flywheel Effect...

As for the readout that comes on your combustion analyzer, there are no less than 100 ways to get to the same point of the combustion curve. Which one is most accurate? None of them. "TRUE THERMAL EFFICIENCY" and the production of or lack of production of CO are the important factors, followed by the equipments ability to sustain comfort while protecting itself from destruction due to condensate errosion, thermal shock and all the other real world conditions that never get checked out in the laboratory are what counts.

Bottom line, in looking at the efficiency of an "burner" is what is the residual O2 content of the flue gasses. If you're doing a good job of combustion, the net O2 should be very low. If you're doing a poor job of combustion, the O2 will be high. If you're doing a good job of taking this rapid oxidation and heat and light generation and converting it into useable thermal energy, you're doing the best that you can do with the given piece of equipment.

As for your coffee pot analigy, you're talking conduction. That's but one of three methods of heat transfer occuring in an gas fired appliance. The primary means of heat transfer occuring at the combustion chamber is radiation, followed by convection. The conductive portion kicks in after taht to conduct those thermal energy transfer into the water. The thermal energy goes through those same transfer traits getting from the inside of the boiler/pipes and into the rooms we're trying to condition, but thats for a whole nuther conversation...

All equipment has it limitations,and one SHOULDN'T exceed that capabilites under normal operating considerations.

Lastly, the 35 PPM CO ambient was coming from roll out from the missing and burnt out combustion tray access doors. Anyone whos ever worked on these fine pieces of crap are familiar with what a pain they are to keep in the proper position. When the input was 200+ % of normal input, there was some flue gas backing out of an area that is normally under pretty substantial negative pressure. Once we lowered the input, the spillage stopped.

I hope you don't consider my long winded response "harping", because there are more people out there who have questions about CO that are afraid to show their ignorance by asking the questions that you have raised. Thank you for doing so. That's how people learn.

As Jim,Tim,Mark,Rudy and a host of others have said and will continue to say, "If you don't test, you don't know, and if you don't know, you're gambling with other peoples lives, possibly your own."

Jeez, maybe I should write an article on this... :-)

Wait a minute, I just did ;-)

TEST TEST TEST TEST TEST

The soap box is now free...

ME

jp_2

experts

if only the experts answered question, they would remain the only experts. you learn by reading & listening, you test your knowledge by speaking. those who only bash never test they knowledge and never improve their knowledge.

how many time have we thought we knew something only to realize half way through an explanation that we are not making sense? forums like this can correct that problem, only if you try.

wow long post, will take some time to get through it. I'll surely have more generalize questions, therefore anyone can give input.

quick question mark, I should have asked weeks ago.
you posted abbout a new installation that had high CO. i remember you cleaned the burner and it helped out. i was curious why a new burner needed cleaning or how you determined a new burner needed cleaning?

Mark Eatherton1

Sheet rock dust..`

is made of gypsum which for the most part is hard to burn. When it mixes with the combustion air, it can foul the oxidation process and CO is the result. In the course of "commissioning" our boilers, we do a combustion test after the construction process is over, and the homeowner is moving in. It's a part of what we label "HO 101". That's when you talk to the owners and tell them what to do in an emergency, and what NOT to do. It was at this time that I discovered the issue with high CO. I can think of maybe two of my competitors that do combustion analysis on their new equipment, and one of them does it because we do, and I taught the other one how to do it. This means that the MAJORITY of my competitors are NOT testing this equipment.

So, in direct response to your question, the dust was from the construction process. Sheet rock dust, hardwood floor dust and so on and so forth.

I determined the need for cleaning by doing a combustion analysis. It was real tempting to NOT test the appliance because it was brand new, but I've developed an attitude that if I don't test, I won't know and someone could die from my lack of attention. I just couldn't live with myself if that ever happened. So, I TEST TEST TEST TEST TEST.

ME

PS, Lint in suspension from a leaky dryer vent, and even pollen can foul the combustion process and cause CO. So, even if it's not new, and nothing appears to have changed, you CAN still produce CO.

TEST TEST TEST TEST TEST

ME