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Troubleshooting and I don't know what to do next

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  • #16
    Re: Troubleshooting and I don't know what to do next

    Bought a BBQ lighter today!

    Cowered beside the open panel to the furnace and held it in front of jet number 1 (where the ignitor is). Nothing at all. So no gas is coming to the first jet.

    Placed a mirror in there to see if the electrode/ignitor was sparking. Yes, it is sparking like mad. Also found something else. There is a flame sensor in front of jet number 1 right beside the ignitor. I did not realize that there was one there as there are no wires running to it and no porcelain base like the other one has in front of jet number 4.

    Tested the solenoids on the gas valve:
    V1 (top, red wire) voltage range is 6 to 27 volts
    V2 (bottom, light blue wire) voltage range is 5 to 13 volts
    Green wire to the valve itself 1.6 volts

    Think I found the water entry - at one corner of the draft fan exhaust hood - what can I use to seal it? - would have to be heat resistant.

    Tomorrow I thought I would find a leather glove somewhere and hold that BBQ lighter in between jet 1 & 2 to see if I can heat up that sensor enough to get solenoid #2 on the gas valve to light up all of the jets. What do you think?


    • #17
      Re: Troubleshooting and I don't know what to do next

      Maybe it's time to call in an heating contractor for a look???

      The thing you think is a flame sensor, Does it have what looks like a very small tube coming out the back of it? How about a way to connect a wire to it?

      You may get it to light up, but will it light up again? I have my doubts. Without a circuit diagram and being able to do more testing, this really is pretty much a guessing game.

      Question: I'm sure the answer is somewhere, but is this a forced draft furnace? If yes, somewhere there should be a draft sensor. They do give trouble now and then and especially if moisture has it stuck.


      • #18
        Re: Troubleshooting and I don't know what to do next

        Good morning,

        Yes, it is a draft furnace, that is why it has a draft inducer blower assembly. This draft inducer/prepurge is wired to two limit switches - first one is on the jet cover plate and has two wires connected to it - second one is a temp (190 degrees, mounted on the back wall and has 3 wires connected to it). Both limit switches read as closed circuits on the ohm tester (the three wire temp one shows closed on the left to top and open on the right to top as it is supposed to do) and both are 25 volts with the volt tester (likely 24 volts as my multimeter is not a cool digital one).

        The switches are giving the control panel permission to light the furnace so that is why the ignitor is trying to light it. Gas valve is not co-operating though.

        It seems to me that because V1 is getting full voltage from the controller, that the controller is asking it to open the gas valve enough for ignition but since I now know that the ignitor is giving spark and also since the lighter didn't work on the jet, that the gas valve is not opening for ignition.

        The two other readings for V2 and Green tell me that power is available to the solenoid and gas valve but not go-ahead until the control panel gets the message that ignition has taken place.

        I think you are right Woussko. Time to call in a heating contractor. I would really like to know exactly what I need (besides a new furnace) before I do though. I am not a wealthy woman and am also part Scottish.

        an aside about the ignitor: Since I could not get a good photo of the ignitor assembly, I took a look on the web and found this one:

        Mine is in the right side column and the 6th one down (FLS4197A). See how it has only one post. That post connects to the ignition system and there is no wire or connection for the flame sensor on it to feed back to the control panel so I'm not sure how it works. But it does appear to be working since the gas valve is refusing to open partially (to allow gas for ignition) and fully (to allow all jets to light).
        Last edited by kathleen; 04-03-2007, 05:41 AM.


        • #19
          Re: Troubleshooting and I don't know what to do next

          Sounds like you may have a bad ground. Where are your voltage readings in reference to? the furnace frame?
          The green wire looks like a ground, if you follow it and it is connected to the furnace frame and ground on the igniter box then you should read 0 ohms (scale set to 200 or so) between frame and all points connected by the green wire (I think bad ground because you read 1.6 V). To determine if the valve is getting power you need to measure the AC voltage across V1 and V2 (one meter lead on each terminal). Also check the voltage were the V1 and V2 wires come out of the igniter, if the voltage differs you may have a bad connection or broken wire.
          Earlier in this post I believe you got the igniter to spark by cleaning the terminals a second time, just wondering if you have cleaned all the terminals on the igniter/control module and the gas valve. It would be a good exercise to pull them all off one by one clean and replace them (avoids the possibility of mixing up the wires). You can make a good cleaner by trimming the end of an emery board down to fit in the connector, clean both sides, spade and connector. Hope you don't live around here as we are in for another blast of winter this weekend, snow and all.
          Last edited by wbrooks; 04-03-2007, 05:56 AM.


          • #20
            Re: Troubleshooting and I don't know what to do next

            Green wire comes from control panel (location on the control panel is the far right hand side and is not marked) and connects to valve. This green wire along with a bright blue wire coming into the cabinet with the thermostat wires (so I think it's a thermostat wire) are joined in a quick connect which plugs directly into the gas valve.

            The only ground I see is a yellow wire coming out of the control box beside the ignitor wire. It is marked GND and is attached to the furnace frame.

            Will test the V1/V2 voltage tonight.

            To test the power coming out of the control board, can I just disconnect the wires leading to the solenoids and then one meter lead to the wire and the other to the cabinet?

            The terminals on the solenoids do look like hell. I will try the emery board tonight after work. Was having trouble getting to them with just the sandpaper as they are encased in a plastic cover. Can I spray Liquid Wrench on the terminals or a Qtip to help clean them up?

            All volt readings were done with the cabinet.

            I am soooooooooooooooooooo grateful for this help. I know that it is a pain to walk a newbie through. Thank you all so much.

            about the snow: Yep, here too.


            • #21
              Re: Troubleshooting and I don't know what to do next

              To test I would leave everything connected and put the meter probes V1/V2 wires (red and blue I think) as they come out of the igniter/controller.
              You should be able to slip the meter probes under the plastic covers where the wire comes out.
              The plastic covers should also slide back off the connector, a bit of wd40 helps them slide up the wires. Liquid wrench and Q-tip won't do much for the connection, the rust needs to be abraded away


              • #22
                Re: Troubleshooting and I don't know what to do next

                You want an electrical cleaner and that's not WD40 or Liquid Wrench. If you have a really good auto parts store near you ask them if they have electrical terminal-contact cleaner. Also an electronics repair or parts shop should be able to sell you a squirt can of Tuner Cleaner which would work pretty well. That darn moisture issue is going to make nothing but trouble for you. Find it and try hard to fix it. Also if you ever see water inside your furnace, try to drill a few small drain holes. Once it does fire up again and gets good and hot that will help dry it for now. Get ready for a big stink as the grime and dust burn off.

                Oh heck, Just call in a good furnace repair tech. Trying this on your own is going to either end up with your not being able to fix it or with POOF or KaBoom and someone gets hurt.

                You would do well to clean up every connection you can and go one at a time making sure nothing gets changed connection wise.


                • #23
                  Re: Troubleshooting and I don't know what to do next

                  Came home and cut up an emery board. What a great idea for cleaning off terminals! Cleaned the two terminals to the solenoids, checked the ignition wire for continuity, cleaned the terminal again at the ignitor and started her up. No flame.

                  Plugged the hole on the fan hood with foil. Hope that takes care of the moisture issue.

                  Shut the furnace down and turned off the gas. Cleaned the terminal on the ground (green wire) and hit the valve (not the solenoid part) with a hammer.

                  Turned the gas back on and then the electricity. Furnace went through all of its sequences and even gave me a nice blue flame across all of the jets.

                  I HAVE HEAT!!!! COME ON SNOW!!!!!


                  • #24
                    Re: Troubleshooting and I don't know what to do next


                    Now go out and get a really nice dinner at your favorate restaurant. You have more than earned it. CONGRATULATIONS

                    Maybe the gas valve was stuck closed and needed a little impacting to free it. I hope you tapped and not hit it hard with the hammer. I'm sure you knew that one.


                    • #25
                      Re: Troubleshooting and I don't know what to do next

                      What?!?!?! And leave my nice warm house?!?!?! OMG Woussko, I couldn't wait to get in here and report back! Didn't realize how heavily this puzzle was weighing on my mind. And am so glad it is over for now.

                      Not sure if it was the ground or hammer that finally did it.

                      I nearly overlooked cleaning the ground terminal because when I pulled off the quick connect it did not appear dirty at all (not brown rust like on the other terminals) but I put the emery board to it anyways and was surprised at all the valve-coloured stuff on there.

                      And the tap with the hammer was a good one but not too too hard. Didn't want to kill it. Only scare it into doing my will.

                      I have picked up some stainless steel screws (couldn't find any with a hex head and had to settle for robertson) and some foil tape to repair some of the environmental damage in there but I will save that for another day. For now I am just basking in warm air.

                      I owe all of you guys a HUGE THANK YOU for all of your great ideas in solving this puzzle, including the forum master for having this place to come where people help one another every day.

                      Thank you all sooooooooooooooooooo
                      very much!!!!!!

                      Isn't it just about AC time?


                      • #26
                        Re: Troubleshooting and I don't know what to do next

                        Originally posted by wbrooks View Post
                        Sounds like you may have a bad ground.
                        I think it was the ground

                        Glad to hear you got it fixed


                        • #27
                          Re: Troubleshooting and I don't know what to do next


                          I think you're correct about the ground connection(s).

                          Kathleen, Please take a look at this and try to get yourself a can or two. A little squirt after the emery board cleaning should really help with your electrical connections.
                 (Good for most of the time)
                          Material Safety Data Sheet:

                 (Popular for marine use and would be good for your use there. Fumes are not too bad.)

                          Down here in the USA you'll find this (especially the first one) at better auto parts stores and in industrial supply houses. I'm not sure up there in Canada, but I'm sure it's around up there too.

                          Be sure to allow it all to evaporate and air some before you apply power. This stuff will burn, so no spraying it near a fire or ignition source. With all of the above give yourself some air. Read the warnings on the label before use.
                          Last edited by Woussko; 04-04-2007, 07:10 PM.


                          • #28
                            Re: Troubleshooting and I don't know what to do next

                            Originally posted by wbrooks View Post
                            I think it was the ground

                            Glad to hear you got it fixed

                            On the next nice day when I am out there taping up, cleaning my terminals so they shine, and putting in my nice new screws I am going to prove you right Wayne. I will take my multimeter with me and take a reading on the ground wire special for you!

                            ALL of you were right in this furnace failure. proplumb, wbrooks and Woussko! First the ignitor wouldn't spark and then the valve wouldn't open. Discovering that my housekeeping on the furnace was neglectful was the best lesson of all to avoid problems down the road. I will be keeping an eye out for the least bit of water entry now you can bet on it.

                            And all these tips on troubleshooting and things to use to work on it - liquid wrench, emery board, contact cleaner (think I'll go with the marine for this outside furnace ), multimeter tests, my own eyeballs - well, I couldn't have done it without each of you and I'm really feeling like Dorothy in Wizard of Oz right now while I thank you all.

                            Bless your hearts for the time you took to consider the problems I presented and then drawing on your own educations and experiences to walk me through to resolve them.

                            You're The Best!!!!!


                            • #29
                              Re: Troubleshooting and I don't know what to do next

                              You haven't seen the bill these guys are gunna send you.
                              I can fix anything with the right hammer or at least break so no one else can fix it