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Possibile Ignition Problem

Kbalz Member Posts: 53
Hi, I have a one-pipe steam boiler, one zone. Its a Burnham from the '60s, but I have a newer digital thermostat. Have been having a randomly occurring problem.

Imagine the system is working fine all day, thermostat is satisfied and boiler turns off. Some time goes by and mother nature cools my house.

Thermostat begins calling for heat, but the boiler is not firing. I hear the circuit "click", but no fire roar. I can hear a faint buzzing, like there is power.

So I turn off the indoor switch, its like a light switch attached to boiler, the buzzing stops. Leave that switch off for about 10 seconds then turn the indoor switch back on.. again I hear the click, but no roar. after a few attempts, eventually the boiler fires!

Once the thermostat is again satisfied, the boiler clicks off. The next request is another gamble.

I've also gotten the boiler to fire, by instead of flicking the near-boiler-switch on and off, I've turned the thermostat on and off. A little nicer since I don't have to go downstairs.

The problem of course is heat is a gamble.. and waking up at 3am to a 59 degree house is not fun.

What should I try, or should I just call someone?


  • BobC
    BobC Member Posts: 5,471
    edited December 2012
    Best call someone in

    Is this a oil fired boiler or a gas gun? It sounds like you might have spark ignition (buzzing sound) and for some reason it's not lighting off the fuel. When it starts does it sound like a loud thud or bang?

    Has the boiler been cleaned recently? It could need cleaning or the electrodes might need adjusting or the ignition transformer could be failing.

    It could be a valve thats become weak and not opening the way it should. You should find a good serviceman and explain you think your having ignition problems, they should be able to figure it out.

    One other question, did this all start right after replacing the thermostat?

    Smith G8-3 with EZ Gas @ 90,000 BTU, Single pipe steam
    Vaporstat with a 12oz cut-out and 4oz cut-in
    3PSI gauge
  • enviro127
    enviro127 Member Posts: 4
    Manually resetting

    the fault condition by turning the main power off and back on, or by resetting the thermostat can be a dangerous way to "fix" the heat.  As mentioned above, calling in an experienced technician would probably be a better option.  The problem could range anywhere from dust in an orifice to faulty gas valve, either of which could cause a significantly larger issue than no heat.  Please update us on the cause and solution to your problem, we would greatly appreciate it!!
  • Kbalz
    Kbalz Member Posts: 53

    Hello again, thanks for the replies. The system is fed by natural gas.

    I should have clarified when I said "newer" thermostat. I meant that it is newer than the boiler, although I did not replace it myself. The thermostat has been working great the previous two heating seasons. I just replaced the AAA batteries over the summer. Its a simple looking honeywell, 1heat/1cold, programmable wake/leave/return/sleep times etc.

    I also should mention I've been hearing a new noise this season, right at the boiler, a knocking. Seems to be after the fire cuts off, within a few minutes I hear 2 -3 knocks. I'll try and get a video of it for the pro to review. Thanks for the advice, I will return to update.
  • vaporvac
    vaporvac Member Posts: 1,520
    May not be Tstat!

    It may have nothing to do with the Tstat. I had the same problem due to a faulty gas valve. The diaphragm would close and due to age wouldn't always open. I could hear the call for heat , but it could be hours or minutes. Tapping it would help jostle it popen. Obviously, that was no way to run a boiler. It finally closed for the last time and since I was replacing the boiler, I didn't bother replacing it.  It was ancient and hard to find, thus expensive.  They must be replaced, not fixed. good luck with your trouble-shooting.Colleen
    Two-pipe Trane vaporvacuum system; 1466 edr
    Twinned, staged Slantfin TR50s piped into 4" header with Riello G400 burners; 240K lead, 200K lag Btus. Controlled by Taco Relay and Honeywell RTH6580WF
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