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The !#$! furnace again...

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  • #16
    Re: The !#$! furnace again...

    Ignition control module clicks (tic tic tic tic) and gas valve should be opening. DO you hear gas valve opening when you hear tic tic tic?

    Is the Inducer motor turning on (small motor @ top left of picture)?

    sequence of operation should be as follows on a call for heat

    1. Thermostat calls for heat
    2. Inducer motor comes on and unit establishes draft
    3. Ignition control module sends spark to igniton assembly (tic tic tic)
    4. Gas valve opens to start flame (gas valve will close in a few seconds if flame not proven).

    If the inducer fan is running and you hear the tic tic tic (and see the spark) but the gas valve is not opening verify that you have voltage to the gas valve at this point (should be 24 volts) if you have voltage and no gas verify gas is supplied to the unit and that the valve is in the on position. If all of this is right and you still have no gas flow the valve is bad and will need to be replaced.

    Troubleshooting by post is tuff

    Comment


    • #17
      Re: The !#$! furnace again...

      Originally posted by OkieBill View Post
      Ignition control module clicks (tic tic tic tic) and gas valve should be opening. DO you hear gas valve opening when you hear tic tic tic?

      Is the Inducer motor turning on (small motor @ top left of picture)?

      sequence of operation should be as follows on a call for heat

      1. Thermostat calls for heat
      2. Inducer motor comes on and unit establishes draft
      3. Ignition control module sends spark to igniton assembly (tic tic tic)
      4. Gas valve opens to start flame (gas valve will close in a few seconds if flame not proven).

      If the inducer fan is running and you hear the tic tic tic (and see the spark) but the gas valve is not opening verify that you have voltage to the gas valve at this point (should be 24 volts) if you have voltage and no gas verify gas is supplied to the unit and that the valve is in the on position. If all of this is right and you still have no gas flow the valve is bad and will need to be replaced.

      Troubleshooting by post is tuff
      Yep. It might be time for me to "call the man". I do appreciate it though as it I am learning things.

      I think you're onto something about the gas valve. Here's the sequence I see:

      1) Thermostat calls for heat. (Yes)
      2) Inducer motor comes on and unit establishes draft. (Yes)
      3) Ignition control module sends spark to ignition assembly. tic, tic, tic,. (NO. I HEAR ONE SMALL TIC OUT OF THE IGNITION CONTROL MODULE. NO FIRE. WAIT X AMOUNT OF SECONDS, I HERE ONE SMALL TIC OUT OF THE MODULE AGAIN. NO FIRE. ETC.
      4) Gas valve opens to start flame. (NO).

      I'll get the meter out and try to troubleshoot the valve as you describe.

      Does the ignitor look broken to you in the last pic from the MicroExplorer? Hard to tell. Got to take some stuff apart to get it out in the open.

      And....What would be a good replacement for this GasPac? Just a generic suggestion is fine based on the very little information you have.

      Thanks.

      J.C.

      Comment


      • #18
        Re: The !#$! furnace again...

        JC, do you still notice the lack of exhaust air volume, the inducer motor could be on the verge of death... As the motor runs the bearings heat up and causes the motor to slow down causing a draft fault, motor cools off and is able to just pull enough RPM's to start system again...

        What voltage is the inducer motor (208V)? Verify proper voltage and amperage at inducer motor

        Bill

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        • #19
          Re: The !#$! furnace again...

          Originally posted by OkieBill View Post
          JC, do you still notice the lack of exhaust air volume, the inducer motor could be on the verge of death... As the motor runs the bearings heat up and causes the motor to slow down causing a draft fault, motor cools off and is able to just pull enough RPM's to start system again...

          What voltage is the inducer motor (208V)? Verify proper voltage and amperage at inducer motor

          Bill
          I may have mislead the doctor. Not intentionally though.

          The inducer motor, (small squirrel cage) is spinning very well with no "common sense" breakdown noise.

          I was feeling the exhaust thinking it related to the induction motor.

          I knew how it normally felt and was not getting that volume. Before I took the covers off and it was in it's running/non-fired cycle-there WAS the normal amount of air volume but it was cold. No fire.

          Thanks.

          J.C.

          Comment


          • #20
            Re: The !#$! furnace again...

            OK so we are at the IGN control.

            Sounds like IGN control is struggling. Verify that the points on the spark assembly have about a 1/4" gap (this is a generalization and can differ based on model and type).

            When you hear the tic do you see a spark at the burner?

            Make sure spark assemble points are not touching burner (grounding out)

            Wiggle spark plug wire and see if you can get the tic tic tic...

            Comment


            • #21
              Re: The !#$! furnace again...

              Originally posted by OkieBill View Post
              OK so we are at the IGN control.

              Sounds like IGN control is struggling. Verify that the points on the spark assembly have about a 1/4" gap (this is a generalization and can differ based on model and type).

              When you hear the tic do you see a spark at the burner?

              Make sure spark assemble points are not touching burner (grounding out)

              Wiggle spark plug wire and see if you can get the tic tic tic...
              Going out to do it now. Had a customer call that likes to talk some.

              J.C.

              Comment


              • #22
                Re: The !#$! furnace again...

                No spark at burner. Not touching either.

                So I pulled the igniter (igniter, right?) out to get a better look at it, put the fuse back in to watch it, listened for the click, no spark on this.

                Does it look right to you? What I mean is I seem to remember the two wires on the left to be looped together. Now that seems to be gone. Yes? No?

                Thanks.

                J.C.
                Last edited by BobsPlumbing; 01-18-2010, 11:40 PM.

                Comment


                • #23
                  Re: The !#$! furnace again...

                  Spark assembly looks good what you looking at from left to right is...

                  1. Spark Rod (bent one) this is where the spark plug wire should attach to.
                  2. The middle one is the ground lead this is where the spark from #1 should be arcing to.
                  3. flame rod , This rod is what helps establish the ground loop when a flame is present, this rod should be in contact with the flame when the burner is lit and should have it's own lead.

                  Comment


                  • #24
                    Re: The !#$! furnace again...

                    change the ignition module
                    sigpic

                    Comment


                    • #25
                      Re: The !#$! furnace again...

                      That Fenwal module is crap, crap, crappity crap

                      The module and igniter will likely set you back a buck 50 (I wouldn't do one without the other) If you can find it's replacement.

                      Think long and hard before you start going down this road....

                      Comment


                      • #26
                        Re: The !#$! furnace again...

                        Originally posted by plumberscrack View Post
                        That Fenwal module is crap, crap, crappity crap

                        The module and igniter will likely set you back a buck 50 (I wouldn't do one without the other) If you can find it's replacement.

                        Think long and hard before you start going down this road....
                        Everything seems to point toward the igniter module dying. What's the right replacement?

                        What I mean is if this one is crap, is there a better replacement?

                        Is this a road better less traveled?

                        Thanks.

                        J.C.

                        Comment


                        • #27
                          Re: The !#$! furnace again...

                          Originally posted by plumberscrack View Post
                          That Fenwal module is crap, crap, crappity crap

                          The module and igniter will likely set you back a buck 50 (I wouldn't do one without the other) If you can find it's replacement.

                          Think long and hard before you start going down this road....
                          Yup Fenwall is crap... I agree. sounds like we are at the IGN module being bad.

                          I strongly recommend a CO check once you can get it to light off again (you can always take the parts back if you need to replace the unit)

                          Next time someone else has to type all of the questions my fingers hurt
                          Last edited by OkieBill; 11-29-2009, 05:57 PM.

                          Comment


                          • #28
                            Re: The !#$! furnace again...

                            Originally posted by JCsPlumbing View Post
                            Everything seems to point toward the igniter module dying. What's the right replacement?

                            What I mean is if this one is crap, is there a better replacement?

                            Is this a road better less traveled?

                            Thanks.

                            J.C.
                            Yes there are better replacements modules BUT....they don't have the same wiring harness. So, you have to cut all 9 wires and adapt them to the new module with plug on connectors. Kind of a pain in the azz. Most Fenwal modules are now obsolete but they used to make a adapter key tab that plugged into your existing harness and adapted to say a Honeywell module.

                            This is for the HSI system but pretty similar
                            http://www.fenwalcontrols.com/utcfs/...eplace_Kit.pdf

                            Comment


                            • #29
                              Re: The !#$! furnace again...

                              Thanks PC. And thanks to all that replied. Especially Okiebill.

                              Rewiring to a new wiring harness doesn't intimidate me. Especially on my own and when it is this old.

                              I'll let all know when I get it running. Sometime between now and April probably.

                              J.C.

                              Comment


                              • #30
                                Re: The !#$! furnace again...

                                As bad as that heat exchanger looks I wouldnt waste the money on an ignition module.

                                Heres my recommendation. http://www.ruud.com/product.aspx?id=...6-EBE891DD5936 This is a real nice dual fuel self contained. I like the Ruud units for their stainless tubular heat exchangers. Mucho better than a mild steel clamshell or tubular.

                                Andy

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