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Boiler locking out

Cosmo_3 Member Posts: 845
I just saw that you mention direct vented. OK, then you mean sealed combustion? If so, this must be a BF-40 Riello. The number one problem I have with oil burners and outside combustion air is that you are bringing in cold air in the winter right to the point of ignition. This is not friendly to atomization of fuel. I had a long conversation w/ Buderus Tech support about this and his suggestion was to increase the size of the combustion intake duct in the mechanical room. Increase the size of the pipe when it gets in to the conditioned mechanical room, and reduce back down before the burner. This will slow down the airflow, and help give the outside air a chance to temper to a higher temperature before going in the burner.

I hear that Viessmann is coming out with a direct vent boiler that actually directs the incoming outside air duct between the boiler jacket and boiler casting, thereby heating the air. I am looking forward to seeing this in the future from other manufacturers as well!

Look up George Lanthier's book on oil burners, great reference material. i think you might find his book either on this site's bookstore, or if not on oiltechtalk's site.
I think George's site is/used to be

Cosmo Valavanis


  • Rob Lussier
    Rob Lussier Member Posts: 4
    boiler problem

    I have a Buderus G-115 direct vent 5 section boiler mated to a Riello 40 series burner that was installed in July '04. After 6 months of use, the boiler locked out. A serviceman cleaned the nozzle, strainer, checked the fuel line, garber filter etc and refired the system. 10 months later, it locked out again. My oil company sent a tech to clean the system thoroughly, and do an O2 and efficiency test. 4 months later, it locked out a third time. Again, a complete cleaning, replacement of nozzle, strainer,filter etc and an efficiency test as well as check of the pressure and overall installation, venting, intake etc. 3 weeks after this service, a rep from Buderus came out to inspect the system. His diagnosis at the time was that the 5 section boiler is too over-sized for my home. (App 85 feet of baseboard, slantfin under kitchen sink, 50 gallon boiler mate for hot water. He said the boiler comes on and off too frequently as it cycles between heating the water and cooling. He timed the heating cycle to app 185 degrees at about 3 to 3.5 minutes. He said the nozzle is sooting up because of the excessive firing of the boiler. He also said there is considerable condensation in the boiler. My oil company thinks I should just pull this system out and replace it with a propane burner. Originally, I had heard that this system was pretty bullet-proof. Any suggestions?
  • Robert O'Brien
    Robert O'Brien Member Posts: 3,537
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  • Joe Brix
    Joe Brix Member Posts: 626

    you could downfire the burner with a slightly smaller nozzle and increase the temp differential to get a longer burn time.
  • Cosmo_3
    Cosmo_3 Member Posts: 845
    short cycling

    What is the heat loss of the house in BTUh's?

    What nozzle size are you running?

    What Brand/model#/size indirect water heater?

    What kind and how many heating zones does your boiler serve?

    What is protecting (if anything) the boiler from low return temperatures under 120F?

    How is the burner controlled?
    Honeywell Triple Aqua-stat?
    Buderus #2109 Control?
    " #2107 Control?
    Something Else?

    Can you take some pictures?

    Sight unseen, I would suggest using a control that will limit burner short cycling, the 2107 would work, or maybe a Beckett heat manager, or a Tekmar product. Also remember that any computerized boiler control must be wired/ programmed correctly for you to take advantage of it's features.

    Cosmo Valavanis
  • EJW
    EJW Member Posts: 321

    It was not a 5 section but I had a 4 section 115 that would lock out also. Buderus rep replaced the blast tube on the Riello with a 10" one, end of problem. How far apart are the exhaust and fresh air inlet outside the house?

  • J.C.A._3
    J.C.A._3 Member Posts: 2,981
    May be a bit controversial in space consumption....

    But I have 2 words for you. Buffer Tank.

    Ask someone who's throwing out the Jacuzzi they used twice, and store the BTU's for when needed.Let the boiler run to it's hearts content and store what you will need for later. Chris
  • Leo
    Leo Member Posts: 770
    If he said

    If the Rep said there was condensation in the boiler what did he say to solve it? There are options. As far as the nozzle sooting up from too much run time what would he say about it happening in a properly sized boiler. I work in the field and service these units. You wouldn't find one in my house.

This discussion has been closed.