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Burner keeps cycling

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dinows
dinows Posts: 10
in Oil Heating

10 year old Beckett oil fired domestic hoy water system, single family home, constant cycling on and off. Replaced all filters, adjusted points and replaced nozzle. Any ideas ??

Thanks very much

Comments

  • Jamie Hall
    Jamie Hall Posts: 27,906

    aquastat?

    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • HydronicMike
    HydronicMike Posts: 453

    Well, what troubleshooting have you performed?
    Define your 'keep cycling'? How often, and for how long?
    What is the water temperature?
    What is the pressure?
    Is there enough water in the system?
    Is the system purged of all air?
    Is the circulator working/moving water, or is the burner just tripping on high limit trying to satisfy a call for heat?

    mattmia2
  • HVACNUT
    HVACNUT Posts: 7,744

    What's the three measurements on the "points"?

    Do you mean "recycle"? Where the burner will start, run for a minute or two then shut off? Then after a minute it starts again? Then the process repeats? What model primary control (the reset button)?

  • EBEBRATT-Ed
    EBEBRATT-Ed Posts: 21,169

    Are you resetting the safety control or short cycling on a normal run? need pictures of what you have.

  • dinows
    dinows Posts: 10
    https://forum.heatinghelp.com/discussion/comment/1904448#Comment_1904448
    https://forum.heatinghelp.com/discussion/comment/1904448#Comment_1904448

    When I say it cycles if I turn the heat up it goes up to set temperature of 180 without stopping then as the temperature starts to drop in the boiler that's when the cycling starts Sometimes you'll hear the burner go on for three seconds and then just shut off The water pressure is 20 plenty of water in the system I purged all the air out the circulator runs The zone valves run as they should This is a Honeywell L7224 The boiler does not make hot water so it goes back to a cold start It keeps the house warm but very annoying the on and off on and off Sometimes it'll run for 20 seconds then shut off I can't figure this out

  • dinows
    dinows Posts: 10
    https://forum.heatinghelp.com/discussion/comment/1904458#Comment_1904458

    The measurement on the points is just under 5/32 of an inch This is a Honeywell L7224 It kicks off at 180 degrees when it calls for heat it does not cycle it goes straight 180 start circulating then the fun begins with the on and off on and off sometimes it will fire for 5 or 10 seconds then kick off and sometimes it will kick on for three seconds without firing and kick off

  • dinows
    dinows Posts: 10

    I can send you a picture i'm not sure what you're looking for

  • 109A_5
    109A_5 Posts: 4,616
    edited September 24

    Is this a new symptom ? Only happens during the shoulder season ?

    Sounds possibly like the Aquastat differential may be too small and/or the boiler is oversized.

    image.png
    National - U.S. Gas Boiler 45+ Years Old
    Steam 300 SQ. FT. - EDR 347
    One Pipe System
  • Jamie Hall
    Jamie Hall Posts: 27,906

    aquastat?

    What I'm reading is that the thermostat comes on, the boiler fires and then runs fine until the water temperature hits 180 — which is probably the high limit of the aquastat. Then the burner starts cycling..

    Without knowing which of several controls or safeties is shutting off the burner, it's a little hard to make an intelligent suggestion — but the first thing I'd look at is finding out if it's the aquastat which is misbehaving.

    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • 109A_5
    109A_5 Posts: 4,616

    If it is the aquastat that is causing the cycling, Honeywell recommends setting the aquastat to the boiler's manufactures recommendations. The settings should be at least verified. Boiler Make and Model ?

    image.png image.png
    National - U.S. Gas Boiler 45+ Years Old
    Steam 300 SQ. FT. - EDR 347
    One Pipe System
  • Big Ed_4
    Big Ed_4 Posts: 3,585

    Too fast and short of a cycle to be a Diff setting . Seems like a short , It may be the aquastat or primary control . While it is happening take the voltage of B1 and B2 in the aquastat , check if the voltage drops out . If so the problem is aquastat back , steady 120V its a primary control problem .. Hope this helps…

    There was an error rendering this rich post.

  • HVACNUT
    HVACNUT Posts: 7,744

    The part where you say "… sometimes it will kick in for three seconds without firing and kick off." is a little concerning. Post a pic of the burner. Is there an oil delay valve?

    The aquastat is a digital control, so the only thing you can check with that (unless you're good with a soldering iron) is tightening all the screw terminals. Shut off the power first. B1 might even have a spade connector. If so make sure its on tight and no burn marks.

    If its oil related, you'll need a pro. When was the last time it was serviced?

  • EBEBRATT-Ed
    EBEBRATT-Ed Posts: 21,169

    Are you sure the system is not air bound?

  • JMWHVAC
    JMWHVAC Posts: 127

    To somewhat sum this up, if a burner “cycles” in seconds, either; 1. The aquastat or connections between it and burner are malfunctioning, which is determined by seeing whether power to burner is dropping out or not. 2. Something on burner is causing it, which most likely would be the primary although other things can also.

  • hot_rod
    hot_rod Posts: 28,524

    A lack of flow caused by a plugged strainer or airlock will also cause short cycling

    Confirm the pump is actually spinning

    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream

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