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I'm curious...

Steve Minnich
Steve Minnich Member Posts: 2,680
Whats the highest CO content you've ever got in a flue gas sample on a boiler?

We had one this morning that buried a Bacharach Monoxor III in seconds. It went immediately to 2000 ppm and then to XXX seconds later.

Turns out the already grossly over-sized (175K in a 1400 sf home), 20 year old copper boiler was over-firing, rolling out everywhere, and caked with soot. Burned control and wires, just a complete mess.

We shut it down in a such a way that it couldn't be turned back on and sold them a new one. All things considered, it was absolutely the right thing to do.

I'm just not sure if I've ever seen one get that high, that quickly.
Steve Minnich
Minnich Hydronic Consulting & Design, LLC
[email protected]

Comments

  • hot_rod
    hot_rod Member Posts: 15,070
    Copper fin tube are famous for plugging under adverse conditions. Is it running a low temperature system, or just short cycling? Or both.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • Abracadabra
    Abracadabra Member Posts: 1,948
    Yep... what @hot rod said. Seen plenty of copper finned teledyne laars mighty therm completely soot up like that recently. The redesigned version runs intake air thru an air filter to reduce the amount of crap that clogs up the fin tube heat exchanger.
  • Steve Minnich
    Steve Minnich Member Posts: 2,680
    Its a Laars. High temp CI radiators. It had to have been short cycling but Tim didn't keep it on long per my instruction. There was a newborn in the home and the CO in the mechanical room was climbing quickly too. Gas valve, S8600, wires were all cooked.

    By the time I get that thing cleaned, tuned in, and replace the controls; the price of that service call is going to be way up there. At that point, I gave them 2 options. Fix this old beat up thing which we would have done gladly if they gave the word or replace the boiler with a properly sized boiler.

    I'm certain the boiler was never touched in 20 years.
    Steve Minnich
    Minnich Hydronic Consulting & Design, LLC
    [email protected]
  • Harvey Ramer
    Harvey Ramer Member Posts: 2,217
    I've hit a handful that made the Bacharach gag. Split mix between lack of makeup air, clogged hx, and bad/dirt in the nozzle.

    Oh, and the one was special. A power venter that could suck a golf ball through a garden hose, mounted on a natural draft system 2000 with a cheap gas conversion burner on it. In their infinite wisdom they caulked every seem in the flue pipe to try and make the Co go away. The mess was ugly.
  • hot_rod
    hot_rod Member Posts: 15,070
    Wear a respirator if you decide to clean the beast, that build up is nasty stuff to inhale. Best to remove the HX and take it to a carwash and blast it clean. Sometimes that crud build up starts to eat away the copper fins. And sometimes young to rod out the tubes if they scaled up inside. Approach with caution!
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • Mark Eatherton
    Mark Eatherton Member Posts: 5,837
    High mass systems (CI rad's) and copper finned tube boilers = condensation production until things get warmed up. Condensate production + the usual garbage in the air = a crud that blocks the flue gas passages and causes roll out. Funny how the roll out protection switch never seems to be in the right place isn't it. A simple bypass will help alleviate the condensation production. Let's face it, EVERY boiler is a condensing boiler when it is first started cold. It comes down to how long it is kept in the condensing mode that dictates longevity between services. And we all know, if it ain't broke, don't fix (service) it...

    As for locking up an analyzer, I've done it numerous times. My Bacharach stopped reading out at 3,000 PPM CO if I am not mistaken. Had a modcon on LP with the silver flex hose that would immediately blow my analyzer up. Ended up having to disconnect the hose to get it to work right, and of course, the factory had NEVER seen that condition before...

    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.
  • Steve Minnich
    Steve Minnich Member Posts: 2,680
    edited December 2015
    @Mark - I'm guessing you may have seen a lot boilers that weren't de-rated properly? Over-firing and then sooting up?
    Steve Minnich
    Minnich Hydronic Consulting & Design, LLC
    [email protected]
  • Steve Minnich
    Steve Minnich Member Posts: 2,680
    Tim pulled it yesterday afternoon and cleaned up (sanded) the existing piping. We'll be installing a cast iron boiler Saturday morning.
    Ideally, and most of the time, it would be a Lochinvar WHN going in. But we do a lot of work in the Austin, Englewood, West Englewood, Gresham, and Washington Park neighborhoods of Chicago; among others. It's always tough times in these areas for the folks who live there. Insert any number of Bruce Springsteen songs here and they would apply.
    Steve Minnich
    Minnich Hydronic Consulting & Design, LLC
    [email protected]
  • Mark Eatherton
    Mark Eatherton Member Posts: 5,837

    @Mark - I'm guessing you may have seen a lot boilers that weren't de-rated properly? Over-firing and then sooting up?

    Actually, I can count those boilers on one hand. A little secret. Our local utility (Excel Energy, PSC of Colorado) pumps air into their gas to derate it. Our gas only has around 830 BTU's per cubic foot, so no, carboning up is not usually the issue.

    There are someplace over on the Western Slope that do have hot gas (1,000 btu's/cu ft) and THEY do have occasional carbon issues. What we do see, due to the derated gas, is double derated, significantly under fired appliances. (Most appliance manufacturers don't know we have derated gas, and if they derate their orifices, then double deration occurs)

    In these situations, sometimes the HXers will condense so bad that they drop condensate on the fire, causing a foul burn and carbon deposition. Now THOSE are nasty, dangerous jobs.

    If you find yourself faced with a dry carbon deposition situation, treat it with EXTREME caution. Those carbon molecules are still burnable, and under the right conditions (dust in suspension) can EXPLODE... Use a HEPA vac to keep the dust contained. If you have to move it (HXer) through the house, wrap it tightly in plastic first to keep it contained until you can get it outside where you can wash the carbon off. In any case, the production of carbon is NOT normal and is an indication of other "issues" that need to be addressed, and most are not real obvious. Improper air/fuel adjustments, improper draft, inadequate combustion air, excess combustion air, vermin (moths, birds, etc.). You MUST check for all of them before you can comfortably walk away from the appliance. If you worked on it last, and God forbid, something goes wrong again, you are holding the bag of liability, and that bag may have decedents in it... You worked on it last, so it becomes your responsibility to prove otherwise...

    Work safe out there, and Merry Christmas.

    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.
  • Steve Minnich
    Steve Minnich Member Posts: 2,680
    Couldn't agree more with being thorough and cautious. I think Tim thinks I'm nuts sometimes because of the lengths/extremes I go through to make sure we leave every piece of equipment we work on in a safe condition.

    I did not know that the gas out west was being derated. Interesting. I wonder how many people working tech support in the midwest or east know about this?
    Steve Minnich
    Minnich Hydronic Consulting & Design, LLC
    [email protected]
  • rick in Alaska
    rick in Alaska Member Posts: 1,250
    I had a Weil Mclain GV boiler that was having problems, ( don't remember what) in a crawl space area of about 5 foot high. I put my analyzer in and it shot up to the overload point very fast. I shut down the unit and jumped out of the space as fast as I could. I waited a while until the area was clear, and then went back in to investigate. It turns out the conversion plate to go from natural gas to propane was just sitting in its bag. I think this boiler had been in for a while like this. I changed the plate , checked the heat exchanger, and re-did my test and it was still very high. After some more checking. I found the termination,the kind with the combustion air intake on the perimeter, to have been installed, but then they put the siding on. The siding was mostly blocking the combustion air intake. I was able to clear around the holes and re-did the test. At this time it was within specs.
    I don't know how the homeowners did not get co poisoning.
    Rick
  • Steamhead
    Steamhead Member Posts: 14,864
    Nice catch, Rick. And in both cases- you can't fix stupid!
    All Steamed Up, Inc.
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
    Consulting
  • njtommy
    njtommy Member Posts: 1,105
    edited December 2015
    I had one last year Power Flame burner. Has soon as I walked in the boiler room it didn't smell right or sound right. The boiler vibrated really bad analyzer went straight 2000ppm or so and shut down.
    Apparently the last person there replace the gas pressure regulator with the wrong spring in it. Also didn't check pressure or tune boiler.
  • Steamhead
    Steamhead Member Posts: 14,864
    edited December 2015
    If it runs with CO that high and a breach or blockage develops in the exhaust pipe, you'll be in trouble. Always expect the worst and tune accordingly. You were the last one to touch it.

    ************************

    I've told this one before, but here it is again:

    There is a small house around the corner from mine, in which I've worked for several owners. Of course it has a steam system.

    Some 15 years ago, I stopped over there to see the lady who owned it then. She opened the front door and the aldehyde odor hit me in the face. When I asked, she said she had just turned the oven on. I told her to shut it down and open the windows, and I'd be right back.

    I went and got my analyzer and some hand tools, tested the oven and stopped the analyzer when it hit 2,500 PPM. Straight, not air-free, and of course it was going right into the kitchen. A few adjustments got it down to less than 50 PPM air-free. The stove was an older Tappan, and they didn't have digital analyzers when it was installed, so over the years she'd been told the odor was "normal" :s Hey, I got your "normal" right here........ also did the top burners, which weren't nearly as bad.

    Several years later, it was in this same house that I first met my wife, The Lovely Naoko. <3

    Good thing I tested that stove, eh?
    All Steamed Up, Inc.
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
    Consulting
    CanuckerMark EathertonGordy4Johnpipe