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  • dead furnace

    It's not dead, just no flame. There is apparently something called a flame rollout switch- where would I find that? I'm working from the schematic, and so far it all checks good, but the 24 volts doesn't make it to the ignitor module. I have an air proving switch, a vent safety switch, and a flame rollout switch- all in series. Two appear to be functional, the third looks like it's open. The furnace picked a cold day to quit.
    I seldom do anything within the scope of logical reason and calculated cost/benefit, etc- I'm following my passion-

  • #2
    Flame rollout will be somewhere around the outside of the furnace fire area.

    On mine it is on the inside of the case where the burners go in from, which is where the sides are open the farthest up. It detects if flame backs up and comes out where it should not (maybe from a blocked flue or pipe)
    2801 3147 6749 8779 4900 4900 4900

    Keep eye on ball.
    Hashim Khan


    It's just a box of rain, I don't know who put it there.

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    • #3
      Ok, I think I know where that one is. More testing-
      I seldom do anything within the scope of logical reason and calculated cost/benefit, etc- I'm following my passion-

      Comment


      • #4
        open switch

        Time now to remove a piece of the vent and get a good look up the flue. It wouldn't be the first time birds nested in there-
        Last edited by darryl; 02-09-2021, 08:27 PM.
        I seldom do anything within the scope of logical reason and calculated cost/benefit, etc- I'm following my passion-

        Comment


        • #5
          What type of furnace? What brand, what model?

          You probably already know:
          Your furnace actually has a safety device that is designed to detect flame. rollouts. It's called a flame rollout switch, and it cuts off the.
          gas supply to your furnace when it detects higher temperatures than normal. immediately outside the combustion chamber.

          Might be some help: https://www.youtube.com/watch?v=d3udy9qZMbg

          Comment


          • #6
            Originally posted by darryl View Post
            open switch

            Time now to remove a piece of the vent and get a good look up the flue. It wouldn't be the first time birds nested in there-
            A long time ago, shortly after we moved into the house, an insurance inspector showed up, and wanted to check a couple things about the electric and furnace. When we went down there, a starling slid out of the front "hood" opening on the furnace and landed on the floor. It then woke up and flew up the stairs, hit a light fixture, knocking the socket out of it so the bulb was there swinging by the wires, and had to be trapped in a first floor room. The insurance guy was enjoying the excitement.

            I figure the bird was knocked out by furnace fumes and fell in. When we had the chimney swept, the guy took out two 5 gallon buckets of old bones of critters that had fallen down into the cleanout area. We had a cap put on the flue.

            Does your flue have a cap? Does the furnace have an open front "hood" on it? Might a critter be stuck in the flue?
            2801 3147 6749 8779 4900 4900 4900

            Keep eye on ball.
            Hashim Khan


            It's just a box of rain, I don't know who put it there.

            Comment


            • #7
              Originally posted by darryl View Post
              It's not dead, just no flame. There is apparently something called a flame rollout switch- where would I find that? I'm working from the schematic, and so far it all checks good, but the 24 volts doesn't make it to the ignitor module. I have an air proving switch, a vent safety switch, and a flame rollout switch- all in series. Two appear to be functional, the third looks like it's open. The furnace picked a cold day to quit.
              I've never seen one quit in during the summer.


              JL...................

              Comment


              • #8
                Originally posted by J Tiers View Post

                A long time ago, shortly after we moved into the house, an insurance inspector showed up, and wanted to check a couple things about the electric and furnace. When we went down there, a starling slid out of the front "hood" opening on the furnace and landed on the floor. It then woke up and flew up the stairs, hit a light fixture, knocking the socket out of it so the bulb was there swinging by the wires, and had to be trapped in a first floor room. The insurance guy was enjoying the excitement.

                I figure the bird was knocked out by furnace fumes and fell in. When we had the chimney swept, the guy took out two 5 gallon buckets of old bones of critters that had fallen down into the cleanout area. We had a cap put on the flue.

                Does your flue have a cap? Does the furnace have an open front "hood" on it? Might a critter be stuck in the flue?
                That's not uncommon. I can remember one cold winter day looking at a few dozen starlings all perched around the edge of the chimney on my uncles house next door. They were all perched facing inward. Then one by one I started seeing some of them get wobbly and fall forward straight down the chimney.

                JL..............

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                • #9
                  I have the furnace running now- it's taking a while to get the inside temp back up. Sometime in the next hour I'll shut it off and check out the flue. There's a dog leg in the flue, so when I get that off I'll be able to look straight up it. I'll have to run the furnace tonite because it's just a bit nippy- minus 12 is what they're calling for. Tomorrow I'll put on a T-shirt and go up on the roof and check out the vent cap. I have my CO detector plugged in right near the furnace. I might put a snap disc in place of the flame rollout sensor temporarily- if it heats and shuts off, I'll hear the difference in the way the thing runs. If it snaps off, I'll turn the furnace off and run some electric heaters for the next day or so.
                  I seldom do anything within the scope of logical reason and calculated cost/benefit, etc- I'm following my passion-

                  Comment


                  • #10
                    If your furnace is newer (sounds like it) , you probably have a flame detector, which could be the problem. I had my furnace quit on a cold winter day. The service guys came out, removed the flame detector, installed a new one, handed me a bill for a little over a hudred bucks, and left me with a warm house. The next day I visited my trusted appliance parts place, bought a spare for twelve bucks, and instructions on how to clean the tip with fine sandpaper. I've cleaned it once since then, and now I'm going to replace it in the fall every two years.

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                    • #11
                      I can't complain. The furnace has done me well for many years. I've had the flue fan seize on me- I pulled it and gave it a complete overhaul, which was no mean feat, and now I lube it often enough. I've had the thermocouple fail to hold the gas valve open- that was a clean and reinstall, and it's been fine. Now I either have a partially blocked flue, or a partially blocked heat exchanger. I suspect the flue, because that has happened before. The house is almost warm now- pretty good since it's damn cold out there right now.

                      I too have never had the furnace fail in summer- but I sure have had my fun with the air conditioner, which is integrated with the furnace. At any rate, I'm glad to have learned more about it all today- the more likely I'll be able to keep it running without having to call in outside help.

                      It doesn't matter now, but for those who asked- this is a Duomatic Olsen. It has high voltage ignition instead of a pilot flame. And I can't blame the furnace for this, but it won't heat if the power goes out- something that has bugged me a bit- isn't that usually when you need heat the most?
                      I seldom do anything within the scope of logical reason and calculated cost/benefit, etc- I'm following my passion-

                      Comment


                      • #12
                        Normally, the furnace has a "hood" that allows a relief point if the flue is blocked. There is generally another rollout sensor up there.

                        If THAT is the one that went out, OK.... flue is a good bet.

                        If it is the lower one near the burners that went out, then blockage in the heat exchanger is more likely.

                        You may have that dratted hot air type furnace, I have hot water, and mine is made as I say. I assume, but do not know, that the hot air types are made in a similar way.
                        2801 3147 6749 8779 4900 4900 4900

                        Keep eye on ball.
                        Hashim Khan


                        It's just a box of rain, I don't know who put it there.

                        Comment


                        • #13
                          Originally posted by darryl View Post
                          There's a dog leg in the flue,
                          Well there you go. When you find the rest of the dog and clean it out you might be back in business!

                          All joking aside we lost our electricity for nearly 24hrs a few weeks ago. It was not extremely cold but hovering around -6 I think. We live in an old home with really thick stone walls. 80cm thick. It is great in the summer for guarding against the heat but when those stone walls cool down it takes a long time to heat it back up! A.K. Boomer ragged on me when I was bragging about my nice cool house with my thick walls. He was right. It took nearly 24hrs to get the house to stabilize after power was restored.
                          Last edited by Black Forest; 02-10-2021, 04:30 AM.
                          Location: The Black Forest in Germany

                          How to become a millionaire: Start out with 10 million and take up machining as a hobby!

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                          • #14
                            Flame rollout switches are commonly a small maybe 1/2" dia disk type switch, commonly have a red reset button on the back side.
                            They are not a common failure item, if they trip there most likely is a problem. Blocked flue, delayed ignition, back draft are just a few common causes.

                            Here is a typical one
                            https://www.acunitparts.com/amana-go...350f-b1370154/

                            Last edited by Sparky_NY; 02-10-2021, 08:16 AM.

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                            • #15
                              My furnace has a rollout fuse that is one and done. I have a 94% Trane furnace and it had the ignitor box fail which made the flame sensor look like the culprit. I was able to replace it and the ignitor with a White Rodgers Universal ignitor box for around a hundred dollars. The flame sensors can get dirty but I don't think you can wear one out.

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