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Beckett CF800 oil nozzle question

Mike_SheppardMike_Sheppard Posts: 527Member
I don’t work on these too often. Much smaller than I am used to seeing. I have a customer with four Weil McLain 80 series sectional boilers with Beckett CF800s. Weil McLain spec’s the burners for 4.5gph Delavan type B 45 degree nozzles at 150 psi, which is also printed on the burner dataplate.

I just took over this property from another contractor and they replaced the nozzles with 4.00 gph 60 degree nozzles and were underfiring them down around 80 psi. According to the customer they claimed they couldn’t get the 45 degree nozzles to burn right.

I adjusted everything I could with the 60 degree nozzles and couldn’t get to zero smoke. On first inspection the diffusers and electrodes were sooted badly. Electrodes were right in the middle of the oil spray. I’ve got good combustion on them now, correct furnace pressure, draft, etc. 5.3% O2 with less than 10 CO, but still getting a #1 smoke.

I believe I should try putting the correct nozzles in and go from there. Is it common to have to move the electrodes further out when using a smaller spray angle?
Never stop learning.

Comments

  • Robert O'BrienRobert O'Brien Posts: 3,129Member
    Never reduce pump pressure below specs. Use Beckett OEM guide and start from there
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  • Robert O'BrienRobert O'Brien Posts: 3,129Member
    Better pic
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  • Mike_SheppardMike_Sheppard Posts: 527Member
    @Robert O'Brien That’s what I’m using to set these up. Then found they had the wrong nozzles in there. I’ll get the correct nozzles and set it all up correctly. Four week lead time on the nozzles...
    Never stop learning.
  • STEVEusaPASTEVEusaPA Posts: 2,988Member
    Along with @Robert O'Brien's excellence advice, make sure that draft is dialed in perfectly.
    Are all 4 boilers in the same mechanical room?
    steve
  • Mike_SheppardMike_Sheppard Posts: 527Member
    Draft is good. They’re all in the same room. Plenty of combustion air. Venting is correct. Furnace pressure is correct. The only things that are wrong are the nozzles and the combustion settings.

    I just wanted to know if I should put the factory soec’d nozzles back in or if there may have been some reason the last company put in 60 degree nozzles and downfired the boilers.
    Never stop learning.
  • STEVEusaPASTEVEusaPA Posts: 2,988Member
    edited July 9
    I agree with @Robert O'Brien to never lower the pump pressure. And logically, why would a wider spray work better on a deep (multi section boiler)?
    Once a bunch of people start monkeying with it usually all bets are off and it’s time to start over from scratch.
    I mention draft only because too much draft will cause impingement. An 1/8” of head movement could make a world of difference.
    I’d have to think they were initially spec'd correctly. Otherwise if I put 4 of these in, WM would be making a visit to make it right.

    If it were me, I’d first check insertion depth, even if it means pulling the burner. You can check the Z dimension at this time, flange/gasket are properly sealing and your 2 degree pitch. I have a small dolly and some wood blocks just for this burner. Check all bolts, all cleanouts, all gaskets, all boilers-yes a giant PIA.

    Then I’d reset back to factory settings, bleed and fire on high fire (of course). Reset pump pressure, steady state, set/lock in draft. Then see where you are with smoke. If you can’t get it to true zero smoke, get it at the best you can. Then I’d try something that I do with Riello's and commercial burners that I learned from the master...George Lanthier.
    With the analyzer in there and eyeing the cad cell ohms, slowly (mm at a time), try moving the head forward, see if it gets better. If it doesn’t, go the other way. One way will make it better, either slightly enlonging or shortening the flame, and/or slightly increasing/decreasing the pressure in the chamber.
    When you get it right, the next 3 will (should) go quicker.
    What is the model # of the WM?
    steve
  • Mike_SheppardMike_Sheppard Posts: 527Member
    edited July 10
    @STEVEusaPA thank you for the advice.

    The boiler is a Weil McLain 80 series 680.

    I’ve got a box of Delavan 45 degree nozzles on the way. I was told they soot up every year and they’re blaming it on the combustion air opening being too small. I measured and calculated and the openings are twice the size required by code. Plenty of combustion air.

    My guess is the main culprit of the smoke is the wrong nozzles and being grossly underfired. They’re supposed to be 150 psi and they had one of them turned down to 60 psi. (I’m going to clean this one tomorrow - 900 degree stack temp). The previous company told them these boilers are small enough that they don’t require cleaning.... I’ll take some pictures.

    I have one more question - the manual for the CF burner has these specs listed for setting the electrodes: 3/16 spark gap. 3/16 above nozzle centerline. 1/4 inch past end of nozzle. I used these settings and it worked great. But that’s on a 60 degree nozzle. Will I have to move the electrodes out further when I switch to a 45 degree nozzle?
    Never stop learning.
  • EBEBRATT-EdEBEBRATT-Ed Posts: 5,857Member
    Check how they light off when you put the 45s back in and see how they light with a cold boiler...that's the ignition electrode test.

    as far a which nozzles to use....this is what I do. Go back to the mfg. original specs and set it up their way for starters it may be fine. Oil pressure should never be below 100psi on any burner so the previous ding a lings didn't have a clue.

    Back to the nozzles. I was a PowerFlame rep back in the day. I can tell you I never found that all manufactures specs were right all the time ...cause they are not. But it's a place to start.

    It costs a lot of man hours and $$$$ to test boiler/burner combinations...so think of this

    Pick any CI boiler you want of the commercial boilers. Start from 4 sections and go to 20 like a Smith 28 for instance. You can buy them with PF, Webster, Carlin, Beckett you name it. Gas, oil or combination. So how many combinations is that? that's like 120 possible combinations.

    Do you really think the manufacturers test all of those? No they do not. They test some and guess the rest.

    Moral of the story is set it up their way to start with if it doesn't work don't be afraid change something. I can name numerous jobs where the "factory settings" didn't work



  • STEVEusaPASTEVEusaPA Posts: 2,988Member
    edited July 10
    @Mike_Sheppard I would leave the electrodes set as per the manual. If you go too far forward they could short out on the end cone. 1/4" actually seems extreme and the max I would even think about.
    That 900° stack temp tells me there's just too much draft and/or too much air.

    Is there enough combustion air for all 4 boilers running and nothing else robbing air from the room? 4 boilers=22 gph (adjusted for pump pressure) X 139,600=3,071,200 btu's.
    How much free opening do you have?
    Quick simple way, with all four running, open the mechanical room door about 1/4". If the door is moving, probably not enough air. More scientific would be with a draft gauge.
    Little info on combustion air requirements:
    https://www.beckettcorp.com/support/tech-bulletins/combustion-air-requirements-for-oil-burners/
    steve
  • Dan FoleyDan Foley Posts: 1,168Member
    @ Mike_Sheppard

    I can’t help you with oil but my lead tech, Brian Golden knows oil as well as anyone. We have many CF burners that he works on. Text me or email me for his cell #
  • SteamheadSteamhead Posts: 13,049Member

    That 900° stack temp tells me there's just too much draft and/or too much air. /

    Or a WHOLE LOT of soot in that boiler. @Mike_Sheppard , post pics of what you find.
    All Steamed Up, Inc.
    "Reducing our country's energy consumption, one system at a time"
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
    Baltimore, MD (USA) and consulting anywhere.
    https://heatinghelp.com/find-a-contractor/detail/all-steamed-up-inc
  • Mike_SheppardMike_Sheppard Posts: 527Member
    edited July 10
    It was a whole lot of soot! I checked draft and everything else beforehand. This is on a military base. They have their own inspectors. From what I am being told is “these boilers are small enough that they don’t require cleaning.” So this was the first cleaning in the lifetime of the boiler....

    Pictures attached. Z dimension was off by over a half inch. Cleaned her out. Reset everything and correct nozzle. Zero smoke and good combustion readings. I will dial it in more when it gets cold outside. They have a four pipe system and run heat year round but not much load to dial it in. Boiler room is about 110 degrees, didn’t want to go to low on the O2 as the boiler room gets cold in the winter.

    @Dan Foley thank you for that. If I have any questions I will reach out. I really appreciate it.

    Picture of combustion readings before and after. 792 degrees stack temp was with a cold boiler just started up. Over 900 after it warmed up. Notice the combustion efficiency change.

    Also, check out the cross-threaded nozzle with Teflon tape on it from the previous company.

    I have so much experience with huge boilers, including oil, the largest I’ve worked on being 1,500 hp. These small ones are foreign to me and I always have to refresh myself when I come across one every few years. I appreciate the help from everyone!
    Never stop learning.
  • EBEBRATT-EdEBEBRATT-Ed Posts: 5,857Member
    Nice job @Mike_Sheppard

    "small boilers don't need cleaning"

    As soon as you mentioned the "80psi" oil pressure I knew the other the other company was NG"

    I will bet it will take a few scrubbings for you to get clean! I hate soot and there is no reason for a mess like that. The other company should be ashamed
  • Mike_SheppardMike_Sheppard Posts: 527Member
    edited July 11
    I work for an air conditioning manufacturer now. Came here to learn chillers for a few years before I try to start my own. They sub contracted all their work out to a competitor of my last company. Now that I’m here they’re giving me all the boiler work and it’s not leaving me enough time to work on chillers lol.

    Two of them had 4 gph nozzles in them, but they’re supposed to have 4.5 gph nozzles set at 150 psi. They had 4gph nozzles, one set at 60 psi one set at 80....
    Never stop learning.
  • SteamheadSteamhead Posts: 13,049Member

    It was a whole lot of soot!

    >:)
    All Steamed Up, Inc.
    "Reducing our country's energy consumption, one system at a time"
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
    Baltimore, MD (USA) and consulting anywhere.
    https://heatinghelp.com/find-a-contractor/detail/all-steamed-up-inc
  • EBEBRATT-EdEBEBRATT-Ed Posts: 5,857Member
    I had one rule when I ran my own business. I would fix up a customers boiler and burner no matter how dirty or screwed up it was.......once! If they didn't call us regularly to service it then they could get someone else. One good soot sucking/ boiler was enough for me
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