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OT: Gas forced air furnace blowing only cold air....any furnace guys here?

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  • OT: Gas forced air furnace blowing only cold air....any furnace guys here?

    5 year old American Standard furnace, no problems until today. Wife says furnace is not heating. It was blowing hot air earlier, then she noticed the air was cold.

    Down to the basement to check all the usual. Reset by turning off power and re-powering a couple minutes later. Cleaned filters. No luck.

    Got on the phone to get a service man out. They're all booked up until Monday after Christmas. But, one service man suggested calling the gas company. They sent a tech out in two hours. Interesting way the gas company works, they'll come out and diagnose for free. If they find the problem they give an estimate and you can take it or leave it.

    Tech is a 35-ish woman, very personable. We chat a bit as she's checking things over. How did she get into furnace repair? Because her phone company job was not looking long term and she heard the gas company was hiring. How did she learn about furnaces? Watching other experienced techs.

    This furnace has a red diagnostic LED that was giving 6 short "on" signals indicating the igniter is bad (according to the manual). She replaces the igniter. Still doesn't work. Then, checking the connector to the igniter she determines there's no voltage. Okay. that means a new main circuit board.

    I've always hated these "replace until you find the bad component" fixes. Is this the way "real" furnace techs work? Maybe I'm being a little hard on her, but the training by watching over another tech's shoulder doesn't impress me.

    She'll be here in the morning with the replacement circuit board. I have no idea what'll happen if it still doesn't work.

    If the problem was only the igniter the charge would have been $250. If it's the circuit board it'll be around $700. Money is money. But, I will be happy if the new circuit board is a fix. Not so happy if it isn't fixed and we go on to the next expensive component.

    BTW, she said these furnace components are readily available, but the suppliers will not sell to the general public, only to furnace techs.

  • #2
    Originally posted by DR View Post
    5 year old American Standard furnace, no problems until today. Wife says furnace is not heating. It was blowing hot air earlier, then she noticed the air was cold.

    Down to the basement to check all the usual. Reset by turning off power and re-powering a couple minutes later. Cleaned filters. No luck.

    Got on the phone to get a service man out. They're all booked up until Monday after Christmas. But, one service man suggested calling the gas company. They sent a tech out in two hours. Interesting way the gas company works, they'll come out and diagnose for free. If they find the problem they give an estimate and you can take it or leave it.

    Tech is a 35-ish woman, very personable. We chat a bit as she's checking things over. How did she get into furnace repair? Because her phone company job was not looking long term and she heard the gas company was hiring. How did she learn about furnaces? Watching other experienced techs.

    This furnace has a red diagnostic LED that was giving 6 short "on" signals indicating the igniter is bad (according to the manual). She replaces the igniter. Still doesn't work. Then, checking the connector to the igniter she determines there's no voltage. Okay. that means a new main circuit board.

    I've always hated these "replace until you find the bad component" fixes. Is this the way "real" furnace techs work? Maybe I'm being a little hard on her, but the training by watching over another tech's shoulder doesn't impress me.

    She'll be here in the morning with the replacement circuit board. I have no idea what'll happen if it still doesn't work.

    If the problem was only the igniter the charge would have been $250. If it's the circuit board it'll be around $700. Money is money. But, I will be happy if the new circuit board is a fix. Not so happy if it isn't fixed and we go on to the next expensive component.

    BTW, she said these furnace components are readily available, but the suppliers will not sell to the general public, only to furnace techs.
    If you can get me the part # I think I have a friend that can get it from Johnstone or another supplier only problem is no heat for the holidays & I'm guessing not too merry like that. Let me know if I can help.
    "Let me recommend the best medicine in the
    world: a long journey, at a mild season, through a pleasant
    country, in easy stages."
    ~ James Madison

    Comment


    • #3
      flylo, thanks for the offer. For now we'll follow through with the gas company since we're already in with them.

      Thinking more about the situation, I've got questions. How is it everybody else in the furnace business is booked and the gas company has a tech here in two hours?

      The gas company deal of free diagnosis seems too good to be true, maybe it is. Do you suppose their techs are so bad nobody uses their services?

      Comment


      • #4
        Originally posted by DR View Post
        5 year old American Standard furnace, no problems until today. Wife says furnace is not heating. It was blowing hot air earlier, then she noticed the air was cold.

        Down to the basement to check all the usual. Reset by turning off power and re-powering a couple minutes later. Cleaned filters. No luck.

        Got on the phone to get a service man out. They're all booked up until Monday after Christmas. But, one service man suggested calling the gas company. They sent a tech out in two hours. Interesting way the gas company works, they'll come out and diagnose for free. If they find the problem they give an estimate and you can take it or leave it.

        Tech is a 35-ish woman, very personable. We chat a bit as she's checking things over. How did she get into furnace repair? Because her phone company job was not looking long term and she heard the gas company was hiring. How did she learn about furnaces? Watching other experienced techs.

        This furnace has a red diagnostic LED that was giving 6 short "on" signals indicating the igniter is bad (according to the manual). She replaces the igniter. Still doesn't work. Then, checking the connector to the igniter she determines there's no voltage. Okay. that means a new main circuit board.

        I've always hated these "replace until you find the bad component" fixes. Is this the way "real" furnace techs work? Maybe I'm being a little hard on her, but the training by watching over another tech's shoulder doesn't impress me.

        She'll be here in the morning with the replacement circuit board. I have no idea what'll happen if it still doesn't work.

        If the problem was only the igniter the charge would have been $250. If it's the circuit board it'll be around $700. Money is money. But, I will be happy if the new circuit board is a fix. Not so happy if it isn't fixed and we go on to the next expensive component.

        BTW, she said these furnace components are readily available, but the suppliers will not sell to the general public, only to furnace techs.
        Just google the part number and you'll find a ton of places that will sell the parts to you wholesale. Oftentimes you can find the stuff on ebay.
        Clean the flame sensor. (The silver looking thin rod that sits in front of one of the burners ) you clean it by polishing it up with sandpaper.

        Comment


        • #5
          I've never had any problems buying repair parts, even from a HVAC wholesaler. I just have to pay retail once in a while. $250 sounds like a lot for an igniter if its just a hot-surface loop. Those usually have visible defects if they're bad. It might be a thermal disc, that will also keep the igniter circuit cold, as well as disable the gas valve. Kinda sounds like the gas company is getting their diagnostic fee in there somehow anyway.

          Comment


          • #6
            If there's an exhaust fan, make sure it's running when the furnace clicks on. Otherwise it won't fire up.
            I seldom do anything within the scope of logical reason and calculated cost/benefit, etc- I'm following my passion-

            Comment


            • #7
              Originally posted by darryl View Post
              If there's an exhaust fan, make sure it's running when the furnace clicks on. Otherwise it won't fire up.
              If it's a high efficiency furnace it will also have a sensor in the fan housing that detects excessive back pressure, a.k.a. squirrel or bird stuck in chimney or flue pipe. Another no flame/no heat condition.

              Comment


              • #8
                As noted igniters are cheap and easily available online. Also, there is a probe that extends into the flame path - if no flame is sensed it cuts the gas. Take some sand paper and clean it up. You should be good to go.

                Comment


                • #9
                  Don't pay for the igniter, ask for your old one to be installed back.
                  Same if the circuit board if it does not work.

                  You should only be expected to pay for the parts that where actually faulty and needed to be replaced. Parts replaced to diagnose things are the repair(wo)mans problem. Clearly she had igniters on hand so she stocks them and didn't cost her anything to test it or take it back.
                  Play Brutal Nature, Black Moons free to play highly realistic voxel sandbox game.

                  Comment


                  • #10
                    If there's a flame sensor, it's likely to be a thermocouple. It's a very low voltage circuit and is used to hold a gas valve open. It can't tolerate even a small voltage drop, so follow the 'wire' back to the gas control box and tighten that connection. Another common problem area.
                    I seldom do anything within the scope of logical reason and calculated cost/benefit, etc- I'm following my passion-

                    Comment


                    • #11
                      When I lived in Puget Sound (Bellevue) I had an American Standard furnace and bought all my parts from an electical shop in Fremont. If he didn't have it then I got it from Grainger. Never had a problem I couldn't fix. I do suspect the technician should have gone into the system after seeing the 6 flashes. It's not unlike having a light fixture that doesn't work. Check the wall outlet for voltage then check the lamp for continuity. This identifies any of multiple probably causes - house wiring (unusual), fuse/breaker (less unusual), lamp wiring (strong possibility), bulb.

                      Comment


                      • #12
                        Originally posted by DR View Post

                        BTW, she said these furnace components are readily available, but the suppliers will not sell to the general public, only to furnace techs.
                        B.S. The first thing I did after having a new furnace installed was to order myself a spare circuit board and a spare igniter. OEM parts straight to my door, no questions asked. All the trouble codes for the blinking LED are spelled out in my furnace owners manual. I'm not going to wait until my furnace dies when it's -20 outside on Christmas eve. Been there done that - not going to do it again.

                        http://www.midwesthvacparts.com/Manufacturer/17-american-standard.aspx?AspxAutoDetectCookieSupport=1

                        Comment


                        • #13
                          Diagnostics are "OK". They tell what the computer "thinks" is wrong.... Doesn't mean that's it. If smart, and it has a hot surface ignitor, then it may flash if the ignitor is open.

                          In your case, A GOOD tech would not just replace, they would measure, if it's not open it's probably good. What the main board "knows" is that it called for current to be in the ignitor and there isn't any. Could be anything from ignitor unit to wire, to circuit board.

                          Gas company is not the best, they have to know everything, and most can't. The company that sells the brand is usually best, as they know it better.

                          I had the gas company check out the furnace years ago. Cleaned it, checked it, went to light it. No light.... Now I knew it was hard to light, but I wasn't home. So tech decides thermocouple is bad. Installs a new one. Still no joy. So tech is talking gas valve, at which point my wife calls me. I told her to get hold of the old thermocouple no matter what the tech says. The tech doesn't have the valve, so he leaves. Wife has thermocouple.

                          I get home, check it out, and sure enough it won't light. So I put in the old one, and do what I normally do, which is to wait 30 sec longer. Furnace lights first time. Guy had installed a high impedance thermocouple but the unit used a low.

                          next day I call gas co and tell them never mind.

                          Bill comes for a bunch of stuff. I write a letter back suggesting I am good with the bill up to where the guy could not light the furnace, and told them I lit it first try with the old theremocouple.

                          Service manager calls me a few days later, and quizzes me, ends up satisfied, and bill is amended.

                          If the guy had come back with a valve, and had installed it, the new valve would have worked, because it would have matched the thermocouple... Genius...bad valve, ... he fixed it, right? NOT!

                          There was nothing at all wrong other than him not knowing how to light the thing. Could have cost a few hundred.... probably had for other folks.
                          1601

                          Keep eye on ball.
                          Hashim Khan

                          Comment


                          • #14
                            For $700 I'd want it done in a basque, stockings and suspenders.
                            There are sure to be cheaper 35ish year old ladies in your area who will happily polish your sensor
                            Mark

                            Comment


                            • #15
                              For $700 I'd want a brand new furnace.
                              "Let me recommend the best medicine in the
                              world: a long journey, at a mild season, through a pleasant
                              country, in easy stages."
                              ~ James Madison

                              Comment

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