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New Gas Boiler "short cycling"

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Ismellelephant
Ismellelephant Member Posts: 3
in Gas Heating

I had a new Weil McLain Cgi PIN 4 gas boiler installed and it appears to be "short cycling". After 3 or 4 visits from the installer they are now claiming this is normal. Recently in 20 degree weather the house only reached 67 degrees despite the thermostat being set to 70 degrees, and all through the night the boiler would shut off and on every 1 to 2 minutes.
Shouldn't this boiler run constantly until the set thermostat temperature is reached?
Purging the air in the baseboard system and a thermostat replacement didn't solve the short cycling. Thanks for any info.

Comments

  • neilc
    neilc Member Posts: 3,173

    did you get air?

    is the circ running?

    post some general pictures,

    system pressure, and temp at boiler?

    known to beat dead horses
  • pecmsg
    pecmsg Member Posts: 7,044

    Is there a 1st and 2nd floor?

  • kcopp
    kcopp Member Posts: 4,670

    Running and firing are 2 different things. Sounds like the boiler is firing but will only give up some heat and not satisfy the zone.

    Could be air. Could be improper circulator/ flow.

  • Ismellelephant
    Ismellelephant Member Posts: 3

    Thanks for the replies.

    There is no air in the system, a purge was done.

    It is a one floor ranch house, one zone and about a 1000 sq ft house.

    Running and firing, when the boiler reaches 160 degrees, it fires up, in about a minute or two it reaches 180 and fires off. The circulator is very quiet but I believe it continues to circulate when the firing is in its off cycle. It just continues this over and over again.

    In 40 degree weather the house will reach set temp even with the 1-2 minute cycling, but in 20 degree weather it fails to reach set temp.

    I understand the firing off and on to satisfy the 160 to 180 deferential. But when there is a call for heat shouldn't the boiler continue to fire until the thermostat set temperature is reached instead of firing off and on?

    This is the system pressure meter

    Meter.JPG
  • Jamie Hall
    Jamie Hall Member Posts: 27,333

    At first impression, either there is still air — in the boiler circuit — or the boiler pump isn't circulating throug the boiler.

    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • neilc
    neilc Member Posts: 3,173
    edited 8:53PM

    can we get a wider shot of the boiler/

    floor to ceiling, showing circ, expansion tank, all in one, maybe from a couple angles

    known to beat dead horses
  • Ismellelephant
    Ismellelephant Member Posts: 3

    I am not at the home right now but will post pics.

    I do know everything was replaced, water regulator, backflow valve, new vents, new circulator, expansion tank. I also asked the installers if the boiler might be oversized and they said it is not.

    Maybe this isn't a yes or no question, but when there is a call for heat shouldn't the boiler continue to fire until the thermostat set temperature is reached? The boiler replaced "seemed" to operate this way and would run for 10 minutes or so till thermostat temp was reached.

  • neilc
    neilc Member Posts: 3,173

    the boiler is hitting the high limit at 180(adj), and shutting the burner down as it should, you're not getting the boiler heat into the house,

    it doesn't sound like you have proper circulation, or there's a bypass, or ??

    did the old heat work to setpoint before the new boiler?

    known to beat dead horses

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