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HB Smith 19A leaking soot

gmcinnes Member Posts: 52
I have an HB Smith 19A. 4 sections, 3.6GPH. Carlin 301CRD burner.

We're getting soot ghosting throughout the house. I haven't heard any puffbacks, and don't see any obvious damage to the boiler. I think there's a "slow" leak of soot somehow.

After taking the service panels off the side, I there's soot on the cast iron sections on one side, and none on the other. The boiler tech who did the last cleaning came back and said the seals must have failed on the cleanouts, which was causing soot to escape. He sealed them up with furnace cement. When the boiler is running I can still feel pinhole leaks from the cleanouts, and from the flange where the flue attaches.

I had a chimney cleaner look at the chimney. He cleaned it and said it is fine, other than the metal liner being a little close (it's within 4 inches) of the chimney cap.


a) Is it acceptable to have small pinhole leaks in an older (14 years) boiler?
b) If the leaks are an issue and should be gone, is this a case of being worth trying to keep kludging along with furnace cement and chewing gum, or should I bite the bullet and look at a new boiler?
c) Should I assume that there will always be soot from any leak? Or is the soot itself an indication of a badly tuned boiler?

Thanks so much for your help,

A confused first time oil boiler guy


    EBEBRATT-Ed Member Posts: 8,548
    Dosen't sound like your tech is on the ball. The clean out covers should be taken off, cleaned and inspected.

    Check the metal clips on the inside, if they get bent too much they won't hold tight. The ceramic rope on the cleanouts may need replacement.

    Other than that some kaowool blanket material will work. I wouldn;t use furnace cement it will just dry out and crack. Red rtv works well on those cleanouts.

    Make sure your tech tunes the burner and uses combustion test equipment.

    There is no reason for soot leaking if properly set up
  • STEVEusaPA
    STEVEusaPA Member Posts: 4,825
    X2 what @EBEBRATT-Ed said. Also, what were the draft readings, over fire and @ breech?
  • SuperTech
    SuperTech Member Posts: 1,581
    The soot is a dead giveaway that your technician did a sloppy job on the cleaning, an inadequate job resealing the boiler and worst of all it sounds like he couldn't be bothered to tune the burner correctly. Soot usually is an indication of high carbon monoxide production. I would question everything this technician claimed to do on your equipment. Sounds like it was better off before he tinkered with it.

    Next time try to make sure whoever touches your equipment has a digital combustion analyzer and is competent enough to leave you a printout of the test results. Then you won't have to worry about soot and carbon monoxide, I'm positive that's not part of what you expected from a "tune up".
  • gmcinnes
    gmcinnes Member Posts: 52
    Thanks so much for your help guys. It sounds like I need another new tech rather than a new boiler.

    The last tech (the one who didn't re-attach the cleanout plates well) did a more thorough job cleaning than my previous guy. And unlike the previous one he did have a combustion analyzer. The readout from it is hard to read, but it says, amongst other things:

    8.4% O2
    36ppm CO
    60ppm CO Air free
    83.7% Eff gross
    62.4% Excess Air
    9.41% CO2
    -- ppm CO Ambient
    66.0 F Ambient

    Any comments welcome on those readings.

    I don't have a readout for the drafts, but he did measure it when he did the work, told me the numbers. But I don't have them written down. He re-measured them when he came out after me calling-back about the soot. It's a Carlin 301CRD burner with forced draft.

    I accept that the soot was because of a sloppy job though. So the questions are:

    a) Can you guys recommend someone reliable for service in the New Haven, CT area?

    b) This soot built up in the house slowly over weeks, and, like boiling frogs, we didn't notice the build up, especially since we were away for two weeks at Christmas. Everything has been cleaned now, but is there any way to say definitively that there's no new soot coming out? I'm anxious to start painting over the stains, but I don't want to do it if this is likely to happen again. Is there anything more useful than hanging a sacrificial white sheet near the boiler to see if it stains?

    Thanks again. It's heartening to see guys dedicated to their trade.
  • SuperTech
    SuperTech Member Posts: 1,581
    I'm not familiar enough with your system to recognize the model number but I wouldn't be proud of those test results unless that is a starting point to improve upon.
    Seeing the blank spot next to ppm CO ambient is concerning because with the burner producing that much CO in the flue I would absolutely want to make sure that no CO is getting into the air that the occupants are breathing!
    Usually I aim for O2 in the range of 5-6.5% with CO2 around 11-12% with CO as close to zero PPM as possible and stack temperature between 450-550 degrees. But most manufacturers have their own specifications.

    You might want to try the find a contractor tool available on this site.
  • gmcinnes
    gmcinnes Member Posts: 52
    @SuperTech I did try the Find a Contractor tool, but I didn't have any luck finding someone within 50 miles.

    I'll try and find someone who can do a better tune up. Is it worth also asking them to do a smoke bomb or something to try and find any other leaks? Or are minor leaks an accepted part of life?
  • SuperTech
    SuperTech Member Posts: 1,581
    I'm sure a test with smoke would work. Kaowool is used throughout the industry to prevent flue gas leakage. Any service access points for the heat exchanger and combustion chamber should be easily sealed with the help of kaowool if the factory gaskets are damaged and not readily available. If you find a decent technician you will have no further worries.
  • gmcinnes
    gmcinnes Member Posts: 52
    Yeah. Find a decent tech. I'm 0 for 2 so far :)
    EBEBRATT-Ed Member Posts: 8,548
    Try @Charlie from wmass but he may not wan't to travel that far especially if he is busy.

    Your combustion #s are not awful but could probably be improved as @SuperTech mentioned.
  • STEVEusaPA
    STEVEusaPA Member Posts: 4,825
    I don't see stack temp or draft. I'll bet the stack temp is too low, causing the fake high efficiency number. Also, air leaks point to the higher CO and lower CO2 number.
    That Carlin should be dialed in much better than that.
  • gmcinnes
    gmcinnes Member Posts: 52
    @STEVEusaPA Sorry, the stack temp is 411.3F I don't have a record of the Draft, although the tech did tell me.
  • Jamie Hall
    Jamie Hall Member Posts: 15,387
    I think there are folks here on the Wall who could do better -- perhaps @dobro23 , who is in Danbury, might be a possibility. @Charlie from wmass is excellent, but I have a feeling he's pretty busy just now.

    On the soot stains and paint, however. A word of caution, from experience. First, clean them off as best you can. They won't vacuum off. There are several pretty powerful household cleaners, such as Spic 'n' Span, which do pretty well -- but they aren't perfect. Then use a really heavy duty stain blocking primer, such as Zinsser's Bin Shellac Base. Almost anything else and the stains will bleed through. They are virtually guaranteed to bleed through any primer or paint which has water cleanup, but they will get through most oil base paints, too.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • gmcinnes
    gmcinnes Member Posts: 52
    @Jamie Hall It's not my first rodeo with this boiler :( Which is part of why I was asking for replacement advice in another thread today.

    We inherited this house, which is circa 1840, and would have been grand in it's day. It's been on a long slow slide since the 1950s though.

    I was about halfway through cleaning and painting every room in the house, which had been soot stained before we inherited, when this incident happened. I'm done. This is an insurance cleanup this time. Appreciate your advice though. I used Bin Shellac before, and will make sure any painters this time do too.

    Added to the fun: We have a toddler, and some of the rooms still have unencapsulated lead paint.
    EBEBRATT-Ed Member Posts: 8,548
    Sadly, @gmcinnes just needs a decent qualified technician. Shouldn't be that hard to find but apparently is.
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