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Dunkirk Q90 boiler gas valve cycles open/closed, locks out if happens too many times in succession

MrRogers Member Posts: 4
I think the boiler is trying to restart when the temperature is still good, so it shuts back off within a second of the gas valve opening. How can I make it wait till it cools a bit before it attempts to re-ignite? I keep hearing the gas valve open then immediately close. Most of the time this doesn't cause a problem, but some times it cycles as described too many times and the computer locks it out, resulting in waking up to a cold house. I checked the condensation drain and it seems to be fine.


  • NY_Rob
    NY_Rob Member Posts: 1,370
    edited November 2018
    Your boiler isn't trying to start early... it's trying to start based on incoming water temp from your radiators.

    You have a "flame out" or "ignition has failed" problem. The system only tries so many times then locks out any further attempts for safety reasons.
  • MrRogers
    MrRogers Member Posts: 4
    Why do I have to turn it off, wait 20 minutes then restart? If I do that, it starts right up and runs. Nothing has changed but the temperature. How can I make it wait to try restart for 20 minutes after maybe three successive restart failures? I mean automatically.
  • ratio
    ratio Member Posts: 3,403
    Sounds more like a flame-loss lockout. What model of boiler? Does it have any error codes or a flashing LED on it somewhere? That should tell you exactly why it's locking out.
  • unclejohn
    unclejohn Member Posts: 1,830
    That boiler needs yearly maintenance by someone who knows what they are doing. Make the call and tell who you call exactly what boiler you have. If the person showes up and his eye's bug out when he see's the boiler sent him packing.