Welcome! Here are the website rules, as well as some tips for using this forum.
Need to contact us? Visit https://heatinghelp.com/contact-us/.
Click here to Find a Contractor in your area.

What defines a "Cycle"

Rob23
Rob23 Member Posts: 1
Hello. I'm new to the forum, but have used it to get some great information on my Buderus G115 WS/5 oil fired boiler.
I'm a little confused as to what defines "short cycling".
Some people seem to refer to only the time the burner is firing as a "cycle".
Others refer to a "cycle" as the time it takes to fire, turn off, and then turn back on.

In my case, with 4 out of 5 zones (circ pumps) calling for heat with a 25 degree outdoor temp day, the burner fires for about 5 minutes, and then shuts off for approx 15-16 minutes. Burner fires up at a boiler temp of 114 and shuts off at about 140.
So the burner fires about 3-4 times an hour.
House is about 3K sq feet, although 500sq feet is a finished basement that rarely has the thermostat on.

Does that seem acceptable?
Thanks for any feedback.

Comments

  • pecmsg
    pecmsg Member Posts: 5,112
    Cycle
    run time + off time. Seeing how it takes almost 15 minutes for everything to stabilize I’d say that’s extremely oversized. 
    ScottSecor
  • hot_rod
    hot_rod Member Posts: 22,820
    Burner on for at least 10 minutes is another rule of thumb. The boiler block and flue needs to get above condensing temperatures durning that period.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
    ScottSecor
  • HVACNUT
    HVACNUT Member Posts: 6,057
    edited November 2023
    Dear Headline, Off, on, off.
  • pedmec
    pedmec Member Posts: 1,009
    Short cycling is a very subjective term. Reason being is i could have a properly size cast iron boiler with say 5 zones for example. With only one zone calling i will run so much of a shorter cycle than if all 5 zones are calling for heat. The same thing could be said for colder days compared to milder days. The boiler is obviously not going to run long on the milder days compared to the colder days. There really are no set standards that i'm aware of.

    I think you have to be an experienced tech to determine whether it's a problem or not. i'm not saying it's good or bad just that it's not a simple determination. Longer cycles are always better for not only the working parts but for comfort. also helps dry out any condensation formed on start-up.

  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 8,576
    edited November 2023
    I would describe a Cycle as the start a series of events until that moment just before it reaches the same point in the series when that same series of events will repeat. Similar to this illustration below
    Ocasionally called a Motor Cycle or a Bi- Cycle or even a Uni- Cycle.
    The Earth also has a Cycle that takes a little over 365 days
    I'm not going to mention my wife's cycle.
    She prefers a Gold Wing, while I'm a HD kind of guy. What cycle did you think I was talking about?

    But you can check it out by clicking on the SPOILER.


    Edward Young Retired

    After you make that expensive repair and you still have the same problem, What will you check next?

  • hot_rod
    hot_rod Member Posts: 22,820
    5 zones cries out for a modulating boiler, on outdoor reset control.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream