Click here to Find a Contractor in your area.
Welcome! Here are the website rules, as well as some tips for using this forum.
Need to contact us? Visit https://heatinghelp.com/contact-us/.

Red staining on chimney exterior - from red dye in oil?

SweetLife
SweetLife Member Posts: 7
I have a Columbia summer winter hook up oil boiler. No one can figure out why I have red staining on the outside of the chimney. From the stain pattern, it is clearly coming from the oil boiler flue. I've had the chimney cap inspected, the chimney swept, verified the stainless steel liner is fine and is the right diameter for the boiler, there is no rust visible anywhere. I found only limited reference on-line indicating that the red dye in the heating oil can cause this problem, but no real info and nothing about how to alleviate it. Help!

Comments

  • STEVEusaPA
    STEVEusaPA Member Posts: 5,464
    Its condensing, has nothing to do with dye. Has anyone checked the flue temperature? Boiler may be underfired, or short cycling.
    steve
  • RobG
    RobG Member Posts: 1,850
    Can you post some photos?
  • SweetLife
    SweetLife Member Posts: 7
    Rob - yes, I'll post some photos later today.
    Steve - but what is condensing that would cause the brown/red stain? I've read up on the flue temperature issue trying to understand it better - and I'm attaching my chart of the readings done by my oil company for the last few years. The flue temp ranges from 432 to 693.
    Questions - 1) I'm confused on what temperature number is important to look at - there is the 'gross' flue temp - the actual temp of the gas in the flue. Then there is the 'net' flue temp - the gross minus the ambient room temp. Then there is the 'instrument' temp - not sure what that is. The 'flue temp' figure on my chart is from the little print out done during the yearly maintenance. Which temp does that refer to? I've read that the flue temp should be in the mid 400's, but not sure which temp that actually refers to (gross vs. net).
    2) I read somewhere that the ExAir number should be between 5% - 20% for oil boilers - mine ranges from 30% to 53%. Thoughts?
    3) I think my draft # is supposed to be about -0.05, mine ranges from -0.04 to -0.0783. Thoughts?
    4) I don't know if these readings are taken at the beginning of the service visit to tell the service person what needs to be adjusted, or at the end of the visit. I'm going to discuss all this with my oil service company, but it would help to understand all this more before I do so.
    Thanks so much for everyone's help - this has been quite the learning process!
    The chimney stucco itself needs to be repaired/replaced, so I'm getting estimates to do that - but before I sink all that money into it, I'd really like to figure out how to prevent the nice new stucco from getting stained.
    Would also like to make sure my boiler is running as efficiently as possible to cut down on oil bills........
  • Jamie Hall
    Jamie Hall Member Posts: 17,842
    Several comments. First, any red dye in the fuel will be destroyed during combustion. So it's not that.

    Gross flue temperature will give you some idea as to whether you will condensation of not. Among other things; it's also part of the measurement of efficiency. Net air temperature influences the draught.

    The other numbers should be measured -- along with oxygen, carbon, monoxide, carbon dioxide, temperature, smoke, and draught at the end of the adjustment procedure. Combined, they will tell your technician -- if he or she knows what he or she is doing -- that your fuel to air ratio is correct, that your draught is correct, and that your system is operating at it's best efficiency.

    It is not possible, in my humble opinion, to do a proper job of adjusting a burner without making these measurements!
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • SweetLife
    SweetLife Member Posts: 7
    Thanks Jamie. Did you take a look at my attachment to my last post? It's a chart outlining all the readings taken at the annual maintenance services. Do those numbers give you any insight? I should add that on another sheet they put down '0' for the smoke number at every service visit.
  • SweetLife
    SweetLife Member Posts: 7
    Whoops - just opened the document I attached before, and it's not the one with the numbers - here it is!
  • STEVEusaPA
    STEVEusaPA Member Posts: 5,464
    edited October 2014
    The numbers for the last 2 years are troublesome, specifically the draft. Did they remove some of the baffles in the boiler? Is the draft regulator working?
    Tell us more about your chimney (like Rob said, pics would help). You said it's lined. Is the chimney outside the building, running up the wall with three sides exposed? How tall? North facing?
    After evaluating the entire heating and venting, the proper answer may be to abandon the chimney and use a power venter.
    I think your first attachment mentions the staining as far back as '08.
    Also, it seems like you have a lot of water side problems. Where are you located? Are you on well water? That would be the only reason for a statement like...the mixing valve only lasts about 2-3 years..
    If that were the case, I'd have to have my service van loaded with mixing valves. :)
    steve
  • JStar
    JStar Member Posts: 2,752
    Are the boiler sections being cleaned? I mean REALLY cleaned? They could be sooting up and restricting proper draft and heat transfer. Then a tech would come in and open up the air band, causing more Excess Air, and higher Stack Temps.
  • icesailor
    icesailor Member Posts: 7,265
    edited October 2014
    That boiler/burner is like a big grey bus, Greyhound bus.

    Oil Burner Techs (or customers that don't expect for higher quality service) that leave things like that are working for the gas conglomerates, the division of the Wall Street Crime Syndicate. I'll bet that there's at least a 2" layer of Kibble & Bits on the bottom of the chamber.

    They have "Draft" red lined at over .07. What's the draft over the fire? The draft over the fire is more important than the draft in the breaching. Especially if you are using high draft in the breeching to overcome the resistance of a dirty and plugged up boiler. I've seen that red stuff in low draft boilers. And if it is a AF or AFG Beckett, and it has very low or positive draft over the fire, they run like crap and will make that red stuff.

    With stack temperatures like that, you aren't getting any condensation in the flue. I've never seen your boiler, but it is leaking so much air into the boiler, that it isn't running properly. It needs to properly and thoroughly cleaned. Some boilers (Weil-McLain 68 Series) carelessly cleaned with a "Soot Saw", can get the sealing between the sections knocked out. It can't be reasonably fixed.

    The wasted use of a good combustion analyzer.
  • SweetLife
    SweetLife Member Posts: 7
    Thanks everyone. More info: When the chimney sweep cleaned the flues, he recommended taking off the old square furnace cap and replacing with a taller, round cap to better fit the round stainless steel liner. He thought this cap may help reduce the staining as less rain to mix with dye and run down outside.
    I've attached photos showing:
    Top of chimney with old cap
    Close ups of removed old cap
    Chimney staining (new cap in place)
    View of house with chimney

    Icesailor: I was the one to red line some of the numbers on the service printouts - thinking those numbers indicated a problem.
    The yearly maintenance record doesn't include a draft over fire number. Should they be noting that? The chimney sweep did take that measurement - said it was -0.02; he also took draft in flue - was -0.07. Sweep also added a weight to the draft flap as there was none there.

    JStar - how do I tell if the boiler sections are being REALLY cleaned?

    Steve - how do I tell if they removed some baffles? And if the draft regulator is working? (note it didn't have a weight on the flapper when the sweep was here last month, he put one on. I don't remember if there was a weight on it in the past or not). Chimney is outside house, 3 exposed sides. Faces SE, but has large holly tree covering face of chimney. Not sure of height - hopefully photos will help you on that issue - it's a split level house, chimney is on the ground level split.

    What are the proper numbers for an oil boiler?
    Flue temp? Net temp? (flue minus ambient?)
    ExAir %?
    Draft? over fire and in flue?

    Thanks everyone - my next annual cleaning is 11/18 and I'd like to be prepared to really question them on what's going on. Also, I have to move forward with repairing the chimney stucco and would love to stop the staining before then!

  • icesailor
    icesailor Member Posts: 7,265
    3 sided outside chimneys are a really bad thing. For Gas, that would be illegal. You may be getting 500+ degrees at the breeching of the damper, but you are condensing in the flue as it goes up the chimney.

    What kind of oil burner and boiler do you have?

    I haven't seen anything like that on a natural draft flue very often. I see it on Power Venters that were running way too much draft because they were oversized for the application.

    billtwocase
  • STEVEusaPA
    STEVEusaPA Member Posts: 5,464
    When the chimney sweep was doing his thing, why didn't he go back up on the roof and check the flue temperature at the top of the chimney with the boiler running?
    The chimney was lined, but it wasn't insulated, which may have prevented your problem.
    --Once again, there's no dye mixing with the rain.--
    -.02 over the fire and -07 @ the breech for that boiler indicates some big problems. Definitely not cleaned properly, or plugged. Many times on a boiler like yours, the baffles burn off/break and fall into the chamber.
    Beside all the things that need to be properly done, I would make sure they pull the entire front panel off, and clean the chamber, and check for integrity. I would also make sure the burner gasket & front panel gasket gets replaced. Check all the baffles for integrity.
    Your final numbers will be based on proper draft (-.01 to -.02 over the fire) and about (-.03 to -.05 respectively at the breech), with true zero smoke. The rest if the numbers will be basically what the are.
    steve
    icesailorZman
  • RobG
    RobG Member Posts: 1,850
    You have gotten some excellent advice in the above post(s). Can you post some photos of the boiler itself?

    Rob
    icesailor
  • SweetLife
    SweetLife Member Posts: 7
    Thanks everyone
    Info on boiler and burner:
    Columbia Emerald EM-125
    Beckett Model AFG

    Note that the label on the boiler says that when using Beckett AFG; draft over fire -0.02, draft in stack -0.0. Is that really what draft in stack should be? Most of the info I've received (including here) is that draft in stack should be -0.03 to -0.05.

    I've attached some photos of the boiler.

    I feel as if at the next service, I need to stand there and watch everything they do and the readings they get. So I appreciate the education you all are giving me so I'm not completely clueless!

    Steve - you asked where I live - Phila suburbs - Berwyn, PA. I'm on public water. Regarding the need to replace the mixing valve every 2-3 years, I thought that seemed odd too, but both plumbers I talked to as well as my oil company said that when I was looking into getting one installed. (Luckily my service contract with oil company covers that).

    As always, any insight, comments, suggestions are most welcome.
  • STEVEusaPA
    STEVEusaPA Member Posts: 5,464
    It's a misprint. Should be -.04 or -.05. As far as the mixing valve, ask the tech to put a pressure gauge on the domestic water to check the pressure
    steve
  • icesailor
    icesailor Member Posts: 7,265

    It's a misprint. Should be -.04 or -.05. As far as the mixing valve, ask the tech to put a pressure gauge on the domestic water to check the pressure

    That may be, but notice how much draft over the fire the AFG requires when compared to the EZ-1 or the Riello. In my experience, .02 DOF with a AFG is asking for trouble. Especially in an osculating wind condition.

    As far as that Mixer, it is NOT heat trapped and is burning out the element.

    A far better solution to the changing mixers would be to install a storage tank, consisting of a cheap 40 or 50 gallon electric water heater direct connected to the potable hot and cold with a lead free circulator pumping water through the tankless and to the tank. You can then run the boiler at lower temperatures. That boiler doesn't look that old. Its noisy because it vents out the top. Is there a rear flue connection on it?

    As far as the draft is concerned, does he get the high draft at the breaching with the gate held wide open? Sometimes, you need to install two RC's if the draft is too high.

    I never had any luck trying to get a AFG to run right with the conditions like yours. I replaced them with EZ-1's. I would also consider the Riello too.

  • Bob Bona_4
    Bob Bona_4 Member Posts: 2,083
    Thoughts are the firebox is eroding. Changed too many Emerald dropped chambers. I wonder what the turbulator baffles are like or even if they exist...possible desinigration of baffles combined with presence of water on top of chimney.

    That boiler was as cheap as cheap could be. Tin can.
  • icesailor
    icesailor Member Posts: 7,265
    "" That boiler was as cheap as cheap could be. Tin can. ""

    Nice looking jacket though.
  • Bob Bona_4
    Bob Bona_4 Member Posts: 2,083
    Emerald Green :)
  • icesailor
    icesailor Member Posts: 7,265
    Made, installed and serviced by Leprechauns?