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Weil McLain UO-3 Help

We inherited a customer for service that has a W/M UO-3 with a Beckett NX. Here is the short of the story:

This boiler continues to soot up like we have never seen, almost every 6 months to the day. This has been an ongoing problem for 3 years. We have only been servicing it now for approx. 18 months.

Here is the tale of the tape:

burner set up and running as per OEM specs- to the letter & verified

all settings and combustion results are within normal range, after servicing and cleaning, then we follow up about 90 days later, still good and all seems great.

Then 90 later, soot like we can't believe.

The combustion air supply is more than ample and clean.

The chimney is a ss lined with a rain cap- also it is cleaned annually.

Fuel supply is clean, no vacuum problems,.

We are not having any "usual" nx burner problems associated with the end cone, the entire gun looks like new every time. No carbon deposits.

Now when I say, we have checked, re-checked and re-checked again EVERYTHING, we have.

We have pretty much ruled out fuel problems, combustion air issues, exhaust issues,

burner setup problems, we looked for any possible environmental contamination from anything in the vicinity of the unit (paints, chemicals, etc.)

Maybe you guys can help us out here, the three of us here are just out of ideas to solve this. Short of putting an OEM Riello burner on, which I may need to add is not an option for our customer, but that's a different story.

Any ideas?


  • Robert O'Brien
    Robert O'Brien Member Posts: 3,541

    What's changed? "No vacuum problems?" Is it two pipe,if so what is vacuum exactly? I would lean toward combustion air/draft/fuel issues these can ad do change over time
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  • billtwocase
    billtwocase Member Posts: 2,385
    that is always a problem

    Weil Mclain wants the burner specs one way, and Beckett another. I would set it to Beckett specs. What are you combustion results, nozzle size, deg angle, spray pattern, pump pressure, etc. I have a few of these out there, 2 are direct vent, and they are a pain in the ****.  I'll take a Gold over those any day
  • Steamhead
    Steamhead Member Posts: 16,899

    What is your draft reading? Does the boiler have a barometric draft regulator?
    All Steamed Up, Inc.
    Towson, MD, USA
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
  • northernboiler
    northernboiler Member Posts: 55

    Unfortunately I do not have a copy of the print out of the combustion analysis results in front of me. However, they are almost dead on after we service the unit.

    The burner is a single pipe gravity feed from a new (3 year old), above ground oil tank. 1/2" line, with a tigerloop installed.

    We set up all of our burners according to the burner manufacturers specs- only.

    We install and service a considerable amount of W/M's golds and ultra's.

    We install way more Buderus, about a ratio of 4 to 1, however this year we probably installed about a dozen ultra oil boilers. But we only use Riello burners. On both W/m and Buderus.

    In my opinion, Riello;s are pretty much bullet proof.

    We do service quite a few W/M ultra oil boilers with the NX burner, I believe they are a fine burner, a little more quirky than the Riello, but if set up correctly and diligently, using the correct settings and equipment they operate fine. They just need a little more time and adjustment.

    From time to time you will hear from other techs at supply houses, how they cannot stand this burner. "too many problems, never works right" and so on.

    Most of the time I just assume some people just do not want to take the proper time, or use the correct equipment to accurately set up the NX burner.

    But we have never encountered a situation like I am describing here.

    No matter what we all do, the result in time is the same. We all believe that something is "changing", oil or draft or combustion air. However we can find no evidence of anything changing. Nothing at all.

    This is what is driving us nuts.

    I just cannot believe that it may be as simple as the burner is just "bad"

    That's why I'm throwing it out here.

    Maybe someone other than us has an idea or an explanation we haven't thought of or have overlooked. Or has some tip we aren't aware of.

    All of us here are professionals, we take pride in our work and really do it correctly.

    As most of the people who post here do as well.

    If we didn't care, we would not be banging our heads against the wall trying to find the cause, going back every month to monitor this. It's driving us crazy that 3 men with a combined experience of almost 55 years are stumped.
  • northernboiler
    northernboiler Member Posts: 55
    combustion results

    here are the numbers from combustion analysis:

    Draft over fire: .02 Breech: .04

    Co2: 11%

    o2: 6%

    stack temp: 387^

    and yes it has a draft reg
  • billtwocase
    billtwocase Member Posts: 2,385
    nozzle specs

    What nozzle is in it, who's specs are you using, and why a tiger loop if it is gravity fed? Like the blue boiler problems, always go with the burner manufacture's settings, not the boiler manufacture's. Is it a true zero smoke when set up?  Does it have the rug on the chamber base area, and updated gun/tube assembly? Any pics?
  • icesailor
    icesailor Member Posts: 7,265
    Soot Mess:

    I can't help you with your NOX/Beckett burner and the soot. But I will comment for the discussion.

    There are some in the trade that are in love with canister type filters and would rather give up their first born son rather than use spin-ons.

    It is my observation and experience that ultra-fine particles in the oil will pass right by some (most/all) canister filters, through pump strainers, and end up in the fine mesh strainers of small oil burner nozzles. If you check the pump pressure, it will always be OK because you are reading the pressure before the strainer and not AFTER the strainer.

    I have fought this problem for years and finally came to this conclusion. Therefore, I put TWO spin-on's on burners and I have NEVER, NOT ONCE had a burner soot up because of a nozzle. The quickest way to find out if this is your problem is when you find a burner that is doing this, take the nozzle out and switch strainers with a new nozzle, and put the old nozzle with the new strainer back. If it runs fine, there's your problem.

    Something to think about. When all else fails, try something new.
  • billtwocase
    billtwocase Member Posts: 2,385
    I would also

    check with Beckett. They have made improvements. You may have one of the that needs the updated adjuster. They would move on their own. 
  • Jim Davis_3
    Jim Davis_3 Member Posts: 578

    Did you do a CO test.  I have seen many oil appliances have zero smoke but have CO in the thousands of ppm.  It is critical on oil to get a CO spike reading when they light, watch the CO the whole run cycle and then watch the spike at the end.  Back in 1984 I learned that a smokeless oil burner isn't necessarily running clean or safe.

    Two things that would definitely contribute would be running at pump pressures below 125# and/or running a 2-line system.
  • rick in Alaska
    rick in Alaska Member Posts: 1,457
    more thoughts

    I am just reading this post and thought I would give a thought or two. What did you do to fix soot issue when it occurred. In other words, did you change the nozzle? I am wondering, along the lines of icesailors post, if it is a fuel related problem and the nozzle is plugging up. I have seen quite a few times when the boiler will go down about 2 days after fill ups because of a plugged or dirty nozzle. I believe as ice said that the fuel delivery will stir up crud that makes its way through the filters and to the nozzle.

     You might check and see what the fuel delivery times are in relation to the boiler sooting up. Maybe you need better filtration.

    p.s. I have this boiler/burner combo for the past 6 years in a direct vent setup and have only touched it 3 times. Runs great, although I still say the nx is not quiet!

This discussion has been closed.