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dunkirk gas boiler issues

johnchandler
johnchandler Member Posts: 3
in Gas Heating

Hi,

We have a dunkirk xeb-4 gas boiler forced water system. Upon turning it first time this fall, there was a burning smell. That went away and now there is a humming noise and the unit don't turn on. I think the draft inducer is dead. Does the draft inducer have to be professionally installed or could I attempt to replace it?

Thanks,

John

Comments

  • Ironman
    Ironman Member Posts: 7,514

    Well, since we don’t know your skill level, how can we know if you can do it?

    Also, how did you confirm it’s the draft inducer that’s bad?

    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 9,157

    I have often heard the when the heater starts humming, that is often because it forgot the words. 🎶 If you can find the sheet music, 🎶 place it near the front of the boiler, 🎶 That may stop the humming.

    Edward Young Retired

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

    IronmanLRCCBJ
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 9,157

    Can you say what part of the Sequence Of Operation (SOO) the boiler fails to get to? This will narrow down the cause of the problem.

    here is the SOO

    1. Thermostat calls for heat, control relay contacts.
    2. Circulator pump is powered through terminals C1 andC2. Control holds off burner and attempts to satisfy thermostat with residual boiler heat.
    3. Induced draft blower is powered.
    4. When blower gets up to speed and blower suction pressure reaches pressure switch set point, pressure switch contacts close sending 24 volts to pilot control from transformer secondary.
    5. Pilot gas valve opens and spark initiates to light pilot burner.
    6. When pilot flame is proven, spark drops out.
    7. Main gas valve opens and pilot burner ignites main burners.
    8. If boiler water temperature reaches high limit set-point, high limit contacts open, cutting power to blower and pilot control. Burners extinguish and blower stops. Circulator pump continues to run as long as the thermostat continues to call for heat. When boiler water temperature drops past the high limit set point and through the differential, high limit contacts close, repeating steps 3-7.
    9. If venting system becomes blocked, blower suction pressure will drop below pressure switch set point, opening pressure switch contacts and cutting power to pilot control. Burners will extinguish, but blower will remain powered as long as thermostat continues to call for heat. If venting system clears, steps 4-7 will repeat.
    10. Thermostat is satisfied, ending call for heat. Relay coil is de-energized, opening contacts. Burners extinguish.Blower and circulator pump stop.

    If you do not get step 3 to happen, you may have a defective control, a defective pressure switch or a defective blower motor. Do you know how to determine which is the problem?

    Edward Young Retired

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

  • HVACNUT
    HVACNUT Member Posts: 6,238

    Even if it is a faulty inducer, is it just a faulty inducer, or was there another cause for the fault? The only way to know for sure is with safety checks and a combustion test. Almost anyone could physically replace it. It's quite easy. But it doesn’t stop there. There's more to it than 4 nuts and a hose clamp.

    SuperTech
  • johnchandler
    johnchandler Member Posts: 3
    edited November 7
    https://forum.heatinghelp.com/discussion/comment/1817644#Comment_1817644

    I had a technician take a look and he said that the draft inducer had gone bad.

    I think I can take the old one out and could try to install a new one. How would I know that it was installed correctly, there is no CO/CO2 leak? The boiler is 15+ yr old, the technician (obviously) said it is good to replace the boiler but I don't want to spend $9k if a $500 repair can do the job.

  • pecmsg
    pecmsg Member Posts: 5,247

    Once that draft inducer is changed combustion analyses need to be performed. At 15 years that heat exchanger needs checking. Do you have those tools and training?

  • johnchandler
    johnchandler Member Posts: 3
    edited November 13
    https://forum.heatinghelp.com/discussion/comment/1818537#Comment_1818537

    I don't. I shouldn't do it myself then. (sry, had a typo)

  • pecmsg
    pecmsg Member Posts: 5,247

    If you don't have the tools and training, HOW can you?

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