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Does "Short Cycling" on a new steam boiler have a negative effect on the lifespan of the boiler?

I am a tenant in an apartment building. The landlord installed a new boiler to replace an ancient, high maintenance, old boiler. The new boiler "short cycles". (10-15 short cycles over the span of 45-60 minutes to raise the apartment temperature 3-4 degrees.) I believe this is costing me extra money to run this new boiler, but I also fear the owner of the building will face a problem of a decrease in the expected lifespan of this new boiler.

Thus my question: Does "short cycling" do damage to a new boiler and left unchecked, will this lessen the lifespan of the boiler?

Thank you,


  • Jamie Hall
    Jamie Hall Member Posts: 17,025
    Cycling like that isn't good. It may not damage the boiler or the burner, but it certainly won't help them -- nor the fuel bill.

    It usually indicates that there is a major problem with system main venting, which is easy enough to fix... if one wants to do it.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • Zipper13
    Zipper13 Member Posts: 214
    it may be a separate issue, but when I moved into my house this winter I found my steam boiler was cycling on/off 5 or 6 times in an hour when calling for heat. come to find out the thermostat the previous owners used was set for forced hot air which is intended to cycle more frequently. the documentation for the thermostat even said "incompatible with steam heat". I found a used thermostat on ebay for $ 20 that had an option to set the type of heat to steam and now it runs longer for once an hour.

    tough to say since weather has been all over, but I do believe we're saving a bit on gas now and it heats faster.
    New owner of a 1920s home with steam heat north of Boston.
    Just trying to learn what I can do myself and what I just shouldn't touch
  • ethicalpaul
    ethicalpaul Member Posts: 3,122
    You said "when raising the temp 3-4 degrees."

    How much does it cycle when just maintaining a temp?
    1 pipe Peerless 63-03L in Cedar Grove, NJ, coal > oil > NG
  • Fred
    Fred Member Posts: 8,518
    If there is a programmable thermostat, make sure it is programmed for steam at 1 or 2 cycles per hour. Also, find a comfortable temperature and leave the thermostat set there. Using set backs and/or increasing the room temp by 3 or 4 degrees will cause the boiler to run longer and exacerbate the short cycling, if the boiler is over sized. Also, find out how many radiators in the building have been shut off. Everyone that has been shut off, make the boiler that much more over sized and that will cause short cycling. Get the radiator vents on each radiator sized properly to deliver the needed heat for each room/area. Don't control the apartment temp by closing off radiators.
    EBEBRATT-Ed Member Posts: 10,235
    edited February 2019
    15 cycles per hour is way too much

    It's probably cycling on 1 of 3 controls, thermostat, pressure control or low water cut off

    Someone needs to find which one.

    1. Crank the thermostat up all the way. See if the boiler runs a longer cycle. If it does it is likely a thermostat cycling issue.
    2. If it cycles when the stat is turned up and left up
    check the boiler pressure gage. If it's building pressure and the pressure changes rapidly you may have an oversized boiler or a venting or piping issue
    3. check the gage glass. It the water level fairly steady? no more than a 3/4"-1" bounce.
    4. If the water level bounces wildly the boiler may need skimming or it could be a piping issue.

    Take a few pictures and post of the boiler and piping

    Short cycling will waste fuel

    It will cause too many expansion and contraction cycles in the boiler & will wear out the burner and controls and ignitor over time
  • drjmaine
    drjmaine Member Posts: 2
    to ethicalpaul: I hope I am replying correctly (I am new to this chat space.) You asked how many times does it cycle when at desired temp. I think it cycles only if the temp drops a degree...then 1-2 cycles and all is well.
  • ethicalpaul
    ethicalpaul Member Posts: 3,122
    edited February 2019
    You’re answering fine. My question was along the same lines as what @Fred said--don't set your thermostat back, just keep it at a constant setting to minimize cycling during recovery.

    Personally, I'm most interested in your main venting situation and your near-boiler piping.

    It's a lot to take in all at once, but read the posts above a few times to start to understand what they are saying. If you need any clarification, just ask here.
    1 pipe Peerless 63-03L in Cedar Grove, NJ, coal > oil > NG