Gas Furnace Flame Jets Start, then Die Out

Discussion in 'Home Repair' started by mrbluelamp@yahoo.com, Feb 26, 2007.

  1. Guest

    I'm trying to get an idea of what my problem might be. The thermostat
    triggers the furnace, one by one the gas flame jets start going, then
    they cut out, then one by one they try to start up again, then they
    all die out except for an orange glow, then the blower comes on and
    shoots out the cold air. I turned off power to my furnace for half an
    hour, and when i turned it back on, and it worked as expected.
    Anybody have any thoughts to the problem?
    , Feb 26, 2007
    #1
  2. Guest

    On Feb 26, 11:20 am, wrote:
    > I'm trying to get an idea of what my problem might be. The thermostat
    > triggers the furnace, one by one the gas flame jets start going, then
    > they cut out, then one by one they try to start up again, then they
    > all die out except for an orange glow, then the blower comes on and
    > shoots out the cold air. I turned off power to my furnace for half an
    > hour, and when i turned it back on, and it worked as expected.
    > Anybody have any thoughts to the problem?


    well it could be a number of things. If you are very low on gas (on LP
    gas) or your pressure regulator (at the supply head) is frozen it can
    easily cause this problem and is most likely. You could also have a
    bad thermal cutoff switch telling your furnace's gas valve to cut
    off.

    best bet is the first option. It really sounds like you're low on gas
    pressure. If you find that your gas supply is just fine and there are
    no problems there- your best bet is to call a licensed professional to
    have them service your furnace.
    , Feb 26, 2007
    #2
  3. PaPaPeng Guest

    On 26 Feb 2007 08:20:18 -0800, wrote:

    >I'm trying to get an idea of what my problem might be. The thermostat
    >triggers the furnace, one by one the gas flame jets start going, then
    >they cut out, then one by one they try to start up again, then they
    >all die out except for an orange glow, then the blower comes on and
    >shoots out the cold air. I turned off power to my furnace for half an
    >hour, and when i turned it back on, and it worked as expected.
    >Anybody have any thoughts to the problem?



    Take a look at your fan belt and see if it actually drives the fan
    when the motor comes on. When the burners fire up and and fan does
    not run, the heat exchanger gets over heated fast. The temperature
    overheat sensor then cuts off the burners. But the part where you
    said that by switching off the furnace and then turning it on restored
    normal function will need a recurrence of the problem to nail down the
    problem.

    Watch for this. The delay in the fan starting up may be due to the
    fan belt being old and glazed, due to incorrect tension or even worn
    bearings. When the opportunity arises you might as well undo the fan
    belt and take out the squirrel cage assembly to do preventive
    maintenance. Use the opportunity to vacuum and wipe clean the furnace
    compartment and to clean the squirrel cage. Note the direction of the
    vanes and reinstall the same way. Take out the bearings and check
    against the shaft for wear. The bearings' holes may be ovalled.

    Should you need to replace the shaft or the bearings do not use any
    grease or lube oil. They are dry bronze bearings and any grease or
    lube will be cooked dry by the heat and cause problems. Replace with
    a new belt anyway as the cost is negilble. Tension the belt so that
    the weight of the motor can just rotate the squirrel cage without
    slipping.
    PaPaPeng, Feb 26, 2007
    #3
  4. dreamchaser Guest

    hmmm, fan belt, I'm not sure his unit is that old. I haven't seen a
    fan belt on a residential furnace ever.

    I agree with the low pressure of the gas, the regulator maybe.

    Another thing that was eluded to is this, the thing that starts your
    fan in heat mode is a temperature sensor in the furnace. When the gas
    first ignites, it heats up the heat exchanger and a temp sensor senses
    that the furnace has warmed up and then turns on the fan. Also, when
    the gas shuts off, the fan continues to run until the temperature
    sensor in the furnace gets down to the shutoff point.

    How long do your burners shoot out flames before they shut off? If
    it's more then about 15 seconds, then the furnace temp sensor that
    tells the fan to come on may have not been working and the burners
    stayed on until the high limit temp sensor cut them out, the furnace
    cooled some and the burners came back on but then the high limit cut
    them out again. I'm guessing maybe the temp sensor that turns the fan
    on was flakey or if your unit is new enough, the electronic board
    malfunctioned and the reset cleared it.

    The high limit temp sensor is a safety and keep the burners from
    running too long without the fan blowing, ie, the furnace would get so
    hot it would burn up the house.
    dreamchaser, Feb 27, 2007
    #4
  5. marcus Guest

    What is the furnace brand? Take the door off and see if there is a LED on
    the board that flashes while it goes through its sequence of operations, if
    so find a trouble shooting guide and follow the instructions.
    Have you had anybody work on it in the past? If so, did they change out the
    control board or fan motor? Some furnaces when you change the intergrated
    control board need a separate wire that comes in another kit, if you change
    the board in A/C you wont notice until Heat that you did it wrong. It could
    also be caused by someone changing the fan motor and not reconnecting the
    ground wire properly.
    Could be the negative pressure switch getting weak and not keeping
    contact.
    If you have L/P make sure it was converted, if not converted, the manifold
    may have gotten clogged with ash and the over temperature switch may be
    tripped. If you have natural gas don't worry about any frezzing valves or
    whatever that guy was talking about.
    My guess would be the negative pressure switch, they are easy to check if
    you have the right tool.
    marcus, Feb 27, 2007
    #5
  6. <> wrote in message
    news:...
    > I'm trying to get an idea of what my problem might be. The thermostat
    > triggers the furnace, one by one the gas flame jets start going, then
    > they cut out, then one by one they try to start up again, then they
    > all die out except for an orange glow, then the blower comes on and
    > shoots out the cold air. I turned off power to my furnace for half an
    > hour, and when i turned it back on, and it worked as expected.
    > Anybody have any thoughts to the problem?
    >

    Do you have a condensate pump (for humidifier runoff) connected to it that
    might be clogged?
    Dimitrios Paskoudniakis, Mar 3, 2007
    #6

Want to reply to this thread or ask your own question?

It takes just 2 minutes to sign up (and it's free!). Just click the sign up button to choose a username and then you can ask your own questions on the forum.
Similar Threads
  1. HvacTech2

    Gas Furnace Flame-Out

    HvacTech2, Oct 19, 2004, in forum: Home Repair
    Replies:
    1
    Views:
    179
  2. jls
    Replies:
    4
    Views:
    277
    pjm@see_my_sig_for_address.com
    Nov 26, 2004
  3. Derek
    Replies:
    17
    Views:
    270
  4. wrlee

    Pilot lights, flame starts, then burns out

    wrlee, Feb 21, 2011, in forum: UK Home Improvement
    Replies:
    1
    Views:
    332
    Andrew Gabriel
    Feb 22, 2011
  5. notbob

    Wasps... die, die, die!

    notbob, Sep 29, 2011, in forum: Home Repair
    Replies:
    28
    Views:
    342
Loading...

Share This Page