furnace problem.... any heating/air guys here??

Discussion in 'Off Topic' started by srdavo, Nov 28, 2009.

  1. srdavo

    srdavo Active Member

    I have a Sears 600 wall furnace. (older...??)
    It has been working fine.

    the pilot remains lit.

    the fan will not turn on..... even if switched to 'Summer' mode.

    the burners will not light.

    the circuit breaker has NOT tripped.

    Could there be a reset button somewhere on this furnace?

    any ideas??

    I just want to rule out anything simple, before I call the landlord. (I don't want to look like a total dummy! )

    any help appreciated.



  2. Take off the outer panel and look for a small red button. If you find one, it is the reset. It is probably the thermocouple (or rarer thermopile). It is the little tube that the pilot light touches with the even smaller tube that runs to the gas valve. It proves to the gas valve that the pilot is lit. When they go bad, the gas valve will not open even with a good pilot light. Remove it and buy a replacement (under $10.00) at any hardware store of the same length or longer, just coil any extra length and tuck the coil out of the way. A thermopile may be harder to find, take the old one with you to the store to match up for type and length. The only indication that it has gone bad is the pilot is lit, but the gas valve won't open and fire the burner.

    I would have to trouble shoot the unit to find why the fan won't run in summer mode. It is possible the two problems are related due to a bad circuit board, depending on the age of the unit. Does it have a permanent pilot light, or does the pilot light come on only when heat is called for? If it is an electronic pilot that doesn't stay lit all the time, then proof of pilot can be by a variety of methods and repair can be complicated and expensive. In that case call the landlord and let him foot the bill.
    Last edited: Nov 28, 2009
  3. machiasmort

    machiasmort Active Member

    The 600 seems to be the General product line... Try to get me the model #... I'll be online for another 20mins. or so...

    Possible there's a reset but there's a few compliants about the rotory switches not making contact.

    If the furnace gave no problems prior (died all at once), I'd look toward the gas valve... There should be a presure switch and they are known to puke! Possible there's a reset on the switch??? Many have O2 sensors that go bad also.

    Know how to read a meter??? LOL! Good luck if your not still on... PM me and let me know how you make out!

    Good idea MBM
    Last edited: Nov 28, 2009
  4. arceeguy

    arceeguy Active Member

    Tough to diagnose a problem without seeing it, but I'll add my opinion.

    While a bad thermocouple may be the culprit, most of the time when a thermocouple goes out, the pilot will go out and you won't be able to keep it re-lit without holding the gas valve in the "light" position because the thermocouple doesn't have the balls to keep the pilot coil on the gas valve open.

    If you've got the wiring diagram, you should proably test any of those "thermo-disc" limit switches. May have a bad one. Or just call the landlord and let him worry about it!
  5. srdavo

    srdavo Active Member


    I'm not finding a reset button..... or a model number. No diagrams either.

    It does have a permanent pilot light. (burning good)

    yup, probably time to call the landlord.

    thanks guys
  6. machiasmort

    machiasmort Active Member

    The "thermo-disc" limit switches are the same switches I spoke of earlier... I'm with AG for a quick look.

    The easy way to do it is shut the power off to the unit (prevents electrocution)! Test the power leads to make sure that the power is off with your meter (be sure to set it to measure AC)!

    After you verify there's no 110 at the wire feeding the unit, set your meter to measure continuity and probe the contacts on the back of the switch while turnning. Not as complicated as it sounds... The switch will either be closed and allow current thru too power the unit or will be open and prevent the current from entering the unit. If you find a switch that don't let the power thru to supply power, thats probably your prob!