Click here to Find a Contractor in your area.
In fairness to all, we don't discuss pricing on the Wall. Thanks for your cooperation.
Need to contact us? Visit https://heatinghelp.com/contact-us/.

Wax on, wax off, wax on...

Mark EathertonMark Eatherton Member Posts: 5,840
Check out the JPEG of the combustion analysis outputs and et me know your thoughts.



I will come back and explain after everyones had a chance to review and comment.



My analyzer locks up at above 3,000 PPM and puts out XXX in the CO category, so all I can tell you is that the CO was above 3,000 ppm.
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.

Comments

  • SWEISWEI Member Posts: 7,356
    hard to read that scan

    But I'm quite interested to learn.
  • Mark EathertonMark Eatherton Member Posts: 5,840
    First one reads

    O2 4.5%



    CO over 3000PPM



    Efficiency 81%



    [email protected] 9.2%



    Stack temp 412



    Air temo 77



    Excess air 25.1%



    Air free CO over 3,000 ppm



    For the record, atmospheric appliance with relatively short stack ~ 8' tall. All other parameters were correct.
    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.
  • Mark EathertonMark Eatherton Member Posts: 5,840
    Second one reads...

    O2 10.1 %



    CO 65 PPM



    Efficiency 81.5%



    CO2 8.1%



    Stack temp = 423



    Air temp 77 F



    Excess air = 83.4%



    AF CO - 125 ppm



    This is the same appliance, with the draft relief hood blocked... Intentionally.
    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.
  • Mark EathertonMark Eatherton Member Posts: 5,840
    Third one reads...

    O2 = 2.1%



    CO above 3000 ppm (XXX)



    Efficiency = 84.5% (ignore)



    Co2 = 10.6%



    Stack temp = 311 F



    Air temp = 76 F



    Excess air = 9.5%



    AFCO over 3,000 ppm.



    Same boiler, under same conditions as the first test of the same boiler, with the relief hood free and open.



    Comments?



    My initial thought was WOW, that burner is doing a REALLY good job of oxidizing the fuel... But if it WERE doing such a good job, why is my CO off the charts?



    As I was taught by people a lot smarter than me, ignore the efficiency readings.



    Thoughts?



    ME
    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.
  • JStarJStar Member Posts: 2,668
    CO

    Not enough draft through the boiler when the hood is free...? Curtain effect?



    The flame is starving in some way.
  • billbill Member Posts: 429
    wax on and off

    What's that ? You can see you are manipulating the equipment. More clues?
  • ZmanZman Member Posts: 4,167
    When do I learn Karate?

    I am thinking the short flue combined with a vent hood rather than a barometric damper is giving you an inadequate draft. This makes it look like you have good efficiency. A bit rich for atmospheric. The co is .the red flag.  When you block the hood the draft improves and it turns out you are to lean. Just add about 20' of insulated flue and you should be all set.

    First cup of coffee.

    Carl



    It looks like the fence could use some paint...
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • Mark EathertonMark Eatherton Member Posts: 5,840
    edited December 2012
    I've heard that term before...

    (curtain effect) and I don't think I've ever heard an explanation of what it is.



    What is your interpretation J Star?



    There are two boilers on this stack, and this boiler is the first boiler (closest to chimney) and the other boiler was manually switched off to exert as much load to this boiler as possible.



    The boiler had been almost completely carboned up due to flash back at the face of the burner, so I had to dis-assemble and clean the whole burner/heat exchanger assembly. I decided to let the burner run for an hour to help clean up the burn before testing. After one hour, it was still showing these same hi CO, low O2 numbers, so I blocked the hood and obtained the second readings. I then removed the relief hood blocker, and the readings went immediately back to the initial findings.



    I guess the point of this exercise is multi fold.



    First and most importantly, these appliances had been worked on by three other "service" companies, all of rather large size (think national franchise) and not one of them recognized this condition... If you don't test, you won't know. If you've not been properly trained on the use of your testing equipment, you won't understand what it is that you're looking at, or what you need to do to correct the situation.



    Secondly, I see this condition so often, it is really scary. Most of these older atmospheric fixed relief hood appliances with short stack conditions run at these conditions ALL THE TIME. It's only when they "leak" CO and someone gets sick, or worse that it becomes a noticed issue.



    These boilers are of the 1970's vintage, and typical of what's in the field. Instead of waiting for the problem to become a problem, why is it not MANDATORY to have ALL gas fired appliances tested and fixed.



    I am recommending complete system replacement as a means of affecting energy conservation on this project, but the simple addition of a barometric damper (with associated spill switches etc) would make a WORLD of difference on the efficiency of these appliances.



    To bill, Wax ON is with the normal factory configuration, fixed, open relief hood. Wax OFF is with the relief hood blocked to exert more draft through the fire box and burners, and Wax ON is duplicating the first condition, fixed open relief hood. Amazing what the addition of a little O2 will do to the burn process. I'm thinking secondary air is also a dead give away.



    Thanks for playing along.



    Before anyone attempts to do this in the field, remember, if you modify it, you own it, and you'd best understand what it is you're doing, and know the consequences of either doing or not doing whatever it is you're going to do to the appliance. This is a STRONG endorsement to get your butt into either Jim Davis or Tim McElwain's class and get trained.



    Ignorance is not a justifiable excuse.



    ME
    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.
  • chapchap70chapchap70 Member Posts: 136
    edited December 2012
    From the oil side

    I spent far more time delivering oil than doing service and have only tested with the Bacharach wet kit but here is what I see for what it's worth.  I have never tested gas equipment fires.



    Is there smoke tests that accompany these?  I know this is an atmospheric burner and that might explain it but there is no way I could get a zero smoke with 9.5% (Third test) excess air with an oil fired power burner.    I doubt I could get zero smoke with 25.1% excess air.  I believe I need about 35% excess air to get a clean fire with flame retention burners.



    I would think that jumping the excess air from 25.1% to 83.4% would lower my CO2 by more than 1.1% (9.2 to 8.1) and increase the stack temp by more than 11 degrees.



    Question:  Before the analyzer became prevalent, did you use the wet kit and would you see this condition with either a smoke test (over fire of course) or by some other means?  Thanks



    Added:  What was the draft?
  • EmpireEmpire Member Posts: 2,343
    edited December 2012
    Good evening Mark.

    Yes Barometric dampers are a MUST in these applications and also apply to other boiler.  As stated draft being created was pulling through open style hood.  Since draft is inadequate, actually all the readings are off.  Co is a given and I normally shoot for 9ppm to 12.5ppm. It depends on the Co2/O2/stack temp/and Excess air, draft, AFCO  Sorry about the rebuttal, it did not up load.
  • Mark EathertonMark Eatherton Member Posts: 5,840
    edited December 2012
    Good question...

    And I'd tell you the answer, except I haven't used a wet kit in over 20 years. ;-)



    But you are correct in that they didn't read CO or AFCO. I'm sure there was a method of calculation AFCO, but it required a separate Monoxor to read the CO.



    The draft on both appliances was right at -.02" WC.



    Also, I've never used a smoke kit on a gas boiler. Maybe someone else has. It went the same way as my wet kit, in to retirement and eventual yard sale...



    ME
    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.
  • icesailoricesailor Member Posts: 7,265
    edited December 2012
    From another side:

    From another side, everything is like ME's lazy former brother in law.They take the path of least resistance.

    If you have two atmospheric gas boilers with draft hoods, connected to the same chimney flue, the one closest to the chimney will always have the better draft. Draft controls (RC-Model M's) can help, but a right handed person will always try to use their right hand. A left handed person that was forced to learn with their right, will always have tendencies to try the left.

    Draft hoods are a terrible way of controlling draft. There is no control. Power vents will always win out in the draft control game. Or a draft making device that vacuum pressurizes the flue, blows positively into the flue but creates negative pressure (draft) to the appliances.

    With both appliances off, you can have equal pressure at both draft hoods, or below the draft hood. When one appliance starts, the draft goes down because of the expanding gas. That doesn't mean that the draft will stay the same in the off appliance.  The draft at the burner and through the flue ways will want to be the same but will probably drop, throwing any adjustments askew. If you apply outside air pressure to the boiler room by mechanical means, you can overcome the negative pressure through the boilers and flue ways but not in the chimney. That causes the building up of flue gasses seen in the examples.

    Every time I see a new install posted here with an atmospheric boiler with a graft hood, I just crack up. They want to save on the cost of oil and switch to gas but won't spend a little more for an efficient boiler with positive draft. In many cases, they are switching out an oil boiler that runs at a higher efficiency  than the atmospheric, open gas burner low efficiency boiler that they switch to.

    Like someone says, "You can't fix stupid.".

    And in spite of the fact that my Bachrach "Insight" digital analyzer does draft measurements, I still drag my wet kit in and use that great big draft gauge that I can see from a long way off.
This discussion has been closed.

Welcome

It looks like you're new here. If you want to get involved, click one of these buttons!