Oven has a pulsing flame

Discussion in 'Shiny Things' started by Attico, Nov 4, 2012.

  1. Attico

    Attico Wrong way 'round

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    Our oven has developed a flame that has a distinct pulse. It is a DCS RGS305.

    The flame is blue and looks like it always has. This oven has been in service for about 7 years. The pulsing doesn't always occur and it is a really fast pulse.

    I don't know much about these things. I just want to be educated before i call the service company. I've read it can be the ignitors that are causing the gas valve to open and close. It seems to ignite ok, but can take a bit of time....

    Any clues?
    #1
  2. KeithinSC

    KeithinSC Long timer

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    Check some other gas appliances, maybe the utility co is having issues?

    Or, make sure you have a proper draft up the exhaust. Flame sensor might have gone wonkey, that can stutter the main valve. Sometimes it just needs to be cleaned and moved back into the 'heart' of the flame.
    Another thing to check is the thermostat, it might be going bad. Try cranking it waay up to see if the flame evens out (temporarily).
    #2
  3. Manuel Garcia O'Kely

    Manuel Garcia O'Kely Back at last

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    Could be low pressure, but only if you are having problems with whole house usually.

    So many ways to control now, it's hard to tell without knowing a lot more about the schematics. Forced air burner or natural draft?

    Could be a clogged filter of somesort.

    How old is the gas supply line?
    #3
  4. Attico

    Attico Wrong way 'round

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    Teh rest of the house seems to be good. I have a bbq/furnace/hot water/gas fireplace and they all seem fine.

    The stove has 5 burners and with all 5 running full blast, they seem to be fine.

    I also didn't see a correlation between the other appliances asking for gas and the stove. Either way it seems consistently inconsistent if that makes sense.

    The burner is an open style so I'll say natural draft (like a BBQ element)

    I turned the oven on to 500 degrees and it made it to that temp, but really took a while.

    The oven sometimes works just fine and heats as quickly as it should.

    I'm thinking it is more the oven since all the other appliances seem to function well.

    The gas supply is 7 years old. The area is about 10 years old, so the supply should be pretty good. I also have my furnace serviced yearly and the tech has never said anything about any supply issues.

    I appreciate the ideas...any more out there?
    #4
  5. Manuel Garcia O'Kely

    Manuel Garcia O'Kely Back at last

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    Can you blow out the burner air mixing area with canned air?

    Take care not to adjust the air shutters.
    #5
  6. Attico

    Attico Wrong way 'round

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    While the oven is lit?

    Is the goal to blow out any debris? I'll try that. I just took video...going to upload to youtube...

    I did find this out. It would be relatively easy to check the ignitor function. They're about $70 online so I may take a chance....am I making sense?
    Pulsating Oven Flame

    It can sometimes happen that the ignitor is just on the verge of allowing the correct amperage to the oven valve, but not quite. In such a case the oven valve can repeatedly cycle open and close quickly, creating a 'pulsating' or sputtering burner flame. Testing for proper amperage draw of the ignition circuit is needed to determine if a 'weak' oven ignitor may be responsible instead of an internal problem with the oven valve itself.


    #6
  7. Attico

    Attico Wrong way 'round

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    Here is the video. you can hear the sputtering quite clearly:

    <iframe width="560" height="315" src="http://www.youtube.com/embed/H7q3JDFUtkU" frameborder="0" allowfullscreen></iframe>
    #7
  8. Manuel Garcia O'Kely

    Manuel Garcia O'Kely Back at last

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    Well, I have to admit that I think the gas valve IS cycling.

    The fact that the gas valve opens at all would make me think...

    Replace the thermocouple/ignitor module and see what happens - they do wear out in time - I had one go bad on a furnace that was not very old, but it was a total fail.

    Could you call the parts counter and ask 'em what they think?
    #8
  9. seuadr

    seuadr Wee-stromer

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    i have to agree with this. thermocouples work on milivolts in most situations, so a variation of just a little can make for a safety signal to the gas valve that switches on and off. the thermocouple itself is pretty cheap to try.
    #9
  10. Attico

    Attico Wrong way 'round

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    Thanks Manuel, Seuadr,

    I found the part I think I need is a Norton 501a flat style igniter.

    Does anyone know if resistance is a factor in these things? In cross referencing a few thje AMPs seem to matter. There was never any mention of resistance values except for one web page with a disclaimer that the generic fit/multi fit has a different resistance.

    The most common igniter for my over seems to be the W13k21 which is a GE/Norton.

    Make sense?

    #10
  11. seuadr

    seuadr Wee-stromer

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    they work off resistance, yes. you should see between 40 and 90 ohms, if they are anything like furnaces. (they likely are) if you read above 90 ohms, then it could be a problem. of course, a quick dirty test is to visually inspect it, you might see a crack and/or a white spot where it has failed. if not, check the resistance.

    depending on the connector, you may be able to replace it with a generic from a supply house like Grainger and then fit in your heat shield/mounting bracket.
    #11
  12. Attico

    Attico Wrong way 'round

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    Cool - sounds like a good thing to try out.

    I'm going to take a chance and buy one today/tomorrow and install it. I'll let you all know how it works out.

    #12