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Mystery Noise in Crown Gas Boiler

trputman Member Posts: 4
Hi All-

We have a Crown Boiler heating hot water radiators. For the past two years, it's periodically made a rattling/vibrating/buzzing noise periodically and stopped, but now it's doing it constantly since it got cold enough for us to fire it up here.

A tech looked at it last year and we replaced a grounding wire to see if that would do anything. When it didn't, he suggested that it may be the ignition transformer vibrating or the pilot igniter trying to refire the boiler (thinking the pilot has gone out). As you can see in the video below, I think the noise is emanating from or near the gray box that I touch at one point.


Thanks for any ideas/feedback! Happy to provide more info if needed.



  • Intplm.
    Intplm. Member Posts: 1,801
    It is quite possible that you may have an intermittent wiring connection. I would check and recheck all connections.
    I would also look to see if there is any debris caught in your gas valve or in the path of your gas supply.
    Sometimes pipe dope, pipe thread tape, or internal rust from the inside of the pipe can flake off and impede gas flow.
    Have the gas inches of water column measured to define the proper flow.

    I'm not sure what could cause a noise like this (listening from a video, and not in the room.) But this is where I would look.
  • mattmia2
    mattmia2 Member Posts: 9,459
    Loose connection in the control wiring or bad contacts in something like an isolation relay or the vent damper or a zone valve would be my guess. you can try jumpering each control one by one or the whole safety chain briefly with a test clip lead while it is running and see if it goes away. do not leave it like that, only do it for a few seconds while you are testing.
  • HomerJSmith
    HomerJSmith Member Posts: 2,395
    edited October 2022
    I would get mechanic's stethoscope and put it on the parts one at a time and try and isolate the noise. You can get one at an auto parts store.
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 7,590
    That buzz noise sounds like there is a 60 hertz electronic vibration that is being amplified by a loose mounting screw on a control or control cover. This vibration is quite normal and is happening on just about every device in your home that has an induction current (something that depends on an electro magnet like motors and relays). Every once in a while, that vibration gets amplified to something that one can actually hear and ofter becomes annoying. As long as it is not annoying, there is nothing you need to do.

    If it is Annoying, then you need to look for a loose screw that is holding one of the control relays or covers onto the metal panels of the boiler.

    Another possibility is a defect in the electrical system that must be corrected. if you have an electrical circuit that is actually acting like a buzzer circuit. That would be a slightly different sound and somewhat louder. This is where the electricity causes an electromagnet to open or close a valve or relay. Immediately upon completing the electrical circuit, the valve action or relay action causes the electric power to stop as a result of a short circuit or open contact. Once the relay or valve returns the the normal (non electrified) position the electric circuit is re-established and the valve or relay is energized again causing the open or short circuit. This will continue until the power is disconnected or the system has a failure.

    If this noise is a result of a short circuit, this should be corrected ASAP. Look for a wire that has been compromised and repair that wire. If it is caused by a defective relay that is having the open circuit, then that control needs to be replaced.

    You need to determine if it is the non problem normal noise tor of it is the second problem. From what I can hear in the video, I believe it is the first non-problem and you jest need to find the loose screw.
    Edward F Young. Retired HVAC ContractorSpecialized in Residential Oil Burner and Hydronics
  • mattmia2
    mattmia2 Member Posts: 9,459
    If this is just something loose that is rattling you will be able to stop it by pressing on things. If there is a contact pulsing caused by a short or some other feedback loop or arcing in the control wiring then pressing on things won't stop it.