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The !#$! furnace again...

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  • The !#$! furnace again...

    Symptom:

    Stat inside calls for heat cycle to begin, but no fire in the box.

    The combustion fan is on, but no fire in the box.

    Next 4 or 5 cycle times, runs and heats normally. (Get aggravated and turn the stat off for awhile-then back on. Sometimes it operates fine for a few cycles, sometimes not.)

    No apparent logic to when the furnace fires or not. Thanks for any input.

    J.C.

  • #2
    Re: The !#$! furnace again...

    Electronics man! They've made life great at times but when they screw up they make life ****ing hell!


    Sounds like something involving a procedure sequence in a control module is the problem.


    You've had some trouble with this furnace.
    Northern Kentucky Plumbers Twitter Feed | Plumbing Videos

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    • #3
      Re: The !#$! furnace again...

      Sounds like an inducer pressure switch issue to me...

      The furnace is periodically not proving draft so no flame. You could pull the rubber/plastic hosse off of the inducer motor housing and first check for any moisture (this will cause intermitent draft faults) then gently exhale and inhale into it and listen for the switch to click (The other end of the hose should be connected to a 2.5" round pressure switch). If you get the click it is time to run the furnace through a couple of cycles and try to get it to fault this time you will verify the fault by using your ohm meter across the contacts of the pressure switch. If the switch Ohm's open while connected to the running inducer assembly at this point you can say the switch is bad and needs to be replaced.

      Disreguard this advice if you are dealing with a Ruud/Rheem furnace and let me know so I can post a different set of troubleshooting ideas. Ruud / Rheem are a different kind of beast...

      Bill
      Last edited by OkieBill; 11-29-2009, 12:57 PM.

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      • #4
        Re: The !#$! furnace again...

        Does it attempt to light the fire? If yes and the fire quickly goes out, it could be the flame sensor is acting up or needs cleaning.

        Comment


        • #5
          Re: The !#$! furnace again...

          Thanks for all replies. I'm not opposed to replacing the whole thing.

          I've even asked more than 1 HVAC contractor on the job if they think I should just yank it. All of them, without knowing one another, say "ride it until it completely dies".

          I think I might take the covers off and take some pics for you to look at. Might help.

          Thanks again.

          J.C.

          Comment


          • #6
            Re: The !#$! furnace again...

            Pictures would be good

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            • #7
              Re: The !#$! furnace again...

              Coming in the next 20 minutes. (Estimate )

              J.C.

              Comment


              • #8
                Re: The !#$! furnace again...

                Pics taken. Loading and posting. (Where's the $@!# USB cords!?!)

                J.C.

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                • #9
                  Re: The !#$! furnace again...

                  First pics. Also have some internal shots with the MicroExplorer (When I find THAT cord. Why do they all have to be at least one pin different? Different subject...)

                  I took pics with it in the burner area and above it. Looks rusty to me. Also took a pic of the igniter the best I could. Get them on here soon.

                  Thanks.

                  J.C.
                  Last edited by BobsPlumbing; 01-18-2010, 11:41 PM.

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                  • #10
                    Re: The !#$! furnace again...

                    Some pictures with the MicroExplorer.

                    First ones are in a couple of the burner chambers underneath the tubes.

                    Others are above the tubes in what I assume is the exchanger area.

                    The final one is the best pic I could get of what I believe is the ignitor.

                    Thanks.

                    J.C.
                    Last edited by BobsPlumbing; 01-18-2010, 11:41 PM.

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                    • #11
                      Re: The !#$! furnace again...

                      Another thing I did and noticed while I had the covers off and the inside stat calling for a heat cycle:

                      I pull the outside fuse, reinstall it, the fan comes on but is not really blowing as much volume out of the exhaust, I hear a "click" but do NOT hear the "zzzpt, click, click, click whoosh off the igniter/burner assembly.

                      J.C.

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                      • #12
                        Re: The !#$! furnace again...

                        JC, is this a gas package unit (Gaspac)? (all HVAC in one box outside)

                        Heat exchanger looks like crap. A visual inspection of the heat exchanger while neat is not very telling. Get a CO meter check on your system ASAP.

                        I can't see how your unit is proving draft but it has to be there and I bet that is the problem Moisture is an even bigger problem in gaspacs.

                        Comment


                        • #13
                          Re: The !#$! furnace again...

                          The ignition control module (grey box with the sparkplug wire) should lock itself out after so many tries for ignition and will need a reset (remove power) to try again.

                          Are you still getting it to fire for the most part or is it now not firing at all?

                          Comment


                          • #14
                            Re: The !#$! furnace again...

                            Originally posted by OkieBill View Post
                            JC, is this a gas package unit (Gaspac)? (all HVAC in one box outside)

                            Heat exchanger looks like crap. A visual inspection of the heat exchanger while neat is not very telling. Get a CO meter check on your system ASAP.

                            I can't see how your unit is proving draft but it has to be there and I bet that is the problem Moisture is an even bigger problem in gaspacs.
                            Correct. It is a "GasPac" system. Furnace on the right, A/C on the left in lamens terms.

                            All one unit together.

                            J.C.

                            Comment


                            • #15
                              Re: The !#$! furnace again...

                              Originally posted by OkieBill View Post
                              The ignition control module (grey box with the sparkplug wire) should lock itself out after so many tries for ignition and will need a reset (remove power) to try again.

                              Are you still getting it to fire for the most part or is it now not firing at all?
                              I have removed power from it. Let set. Reinstalled fuse. Fan comes on, then a few seconds later the ignition module "clicks", and that's where the cycle ends. No fire at all.

                              Thanks.

                              J.C.
                              Last edited by BobsPlumbing; 11-29-2009, 03:59 PM.

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