Top Nav

Problem: Furnace main burner ignites, the main burner stays on for 8 to 10 seconds, then shuts right back off

Problem: Your furnace main burner ignites, the main burner stays on for 8 to 10 seconds, then shuts right back off. Your furnace tries this ignition sequence again, and the same thing happens. After 3 times the furnace goes into lock out, and the only way to get it out of lock out is to turn the power switch off and on. Everything starts over again without ignition of your gas burners.

Solution: First, turn off the power to your furnace. Check all wires and ground wires to make sure they have good tight connections and are not burnt. Next, remove the screw or screws that hold your flame sensor in. Please do not confuse the flame sensor with an Ignitor. We do not want to touch the ignitor at all. If you touch an ignitor it will shorten the life of the ignitor or it will break. Below this paragraph we have a picture comparing an ignitor with a flame sensor. Clean your flame sensor with steel wool or emery cloth (fine sand paper). You might need a new flame sensor, but most of the time they can be cleaned and your furnace will work well after cleaning. I have seen flame sensor go out. Most of the time when they go out the white porcelain is cracked. You might want to have a spare flame sensor on hand. Here is a link to our Flame Sensors Page: Please click hear to go to our Flame Sensors Page or you can click on the flame sensor picture below. Near the bottom of this page we have a YouTube video on how to troubleshoot, clean and change-out a flame sensor.

Thanks! We would Love to Have Your Business!

Below is a picture to help you identify what a flame sensor looks like and what an ignitor looks like. Below is a picture comparing flame sensors on the top with an ignitor on the bottom. We do not want to touch the gray glass part of the ignitor or it will shorten the ignitor’s life or it might break.


flame sensor


Please click here to go to our furnace ignitors page.

Below we have a YouTube Video on how to troubleshoot and clean a flame sensor:

15 Responses to Problem: Furnace main burner ignites, the main burner stays on for 8 to 10 seconds, then shuts right back off

  1. Anthony November 27, 2015 at 12:32 pm #

    Burners light for a few seconds then go out. I cleaned the flame sensor and it worked only a couple times, and problem returned. I replaced the sensor with a new one, it worked then problem has now returned again. Could it be another issue?

    • Steve Arnold November 27, 2015 at 1:49 pm #

      Hi Anthony! Please make sure that the ground is good on your furnace and all connections are good and tight. A burner flame that is not good and blue and not touching the flame sensor can cause the flame sensor to not sense a good flame. Please make sure the flame sensor is sitting in a good hot blue flame when the burners come on. Sometimes the problem can be in the control board. Best of luck in finding the problem.

  2. L November 26, 2015 at 8:44 am #

    Thanks, this tip on cleaning the flame sensor kept my thanksgiving warm!

    • Steve Arnold November 26, 2015 at 8:47 am #

      Awesome! Glad to hear you fixed your furnace by cleaning the flame sensor! Thanks so much for letting me know our page helped you out! Hope you and your family have a blessed Thanksgiving and Christmas Holiday! Steve

  3. Jesse November 22, 2015 at 3:54 pm #

    My burners work fine while the cover is off but they go out soon after I put it back on. I can feel it pulling air through when it is cracked. When the cover is on it will burn out then ignite Every minute or so. What could be wrong.

  4. Jason Ralston November 22, 2015 at 12:22 am #

    I have a comfort maker main burner kicks on for about 15 seconds (3 times) then the second one kicks on for about 30 seconds and the both go out. I have replaced the flame sensor, gas valve ( smart valve) ,pressure switch . I don’t know what else to try.

    • Steve Arnold November 22, 2015 at 6:10 am #

      Hi Mr. Ralston! Since that you say one burner kicks on for about 15 seconds and the second burner kicks on for about 30 seconds this tends to make me believe that you do not have enough or you have too much gas pressure coming out of your gas valve. Normally, both burners should light at the same time and burn continuous until the wall thermostat is satisfied. Your furnace gas is probably cutting off because the flame sensor is not sensing the flame on the burners so it tells the control board to cut the furnace off. Adjusting gas pressure can be dangerous. I would suggest leaving this to a professional who has a Water Column gage. Here are some links to some YouTube videos if you feel comfortable in trying yourself: Best of luck in fixing this problem. I hope you have a great day! Steve Arnold

  5. DANTE November 19, 2015 at 2:17 pm #

    I got a 2yr old Goodman…its goes through the cycle properly….after the blower comes on for maybe 30-40 seconds…the burners goes out…..I change the pressure switch…flame sensor and control board…..and its still cutting out early….I check the flute pipe…and voltage…….still cuts out…..I’m all out of ideas as to what is happening..

    • Steve Arnold November 20, 2015 at 6:26 am #

      Hi Dante! About the only way to find out for sure where the problem is would be to use a volt meter. If you do not have a volt meter it will be a guess as to where the problem is located. I would suggest that you purchase a low cost multi-meter at Home Depot, Radio Shack or other electronics store. When you get the meter I would suggest sitting it on “Volts AC”. Tape the furnace blower door safety switch down so you can get power to the furnace with the blower door open. Turn the thermostat up for heat and test between the thermostat wires W (white) and C Com (usually purple or blue on Goodman). You should get a constant 24 to 28 volts AC between the W and C terminals when the thermostat is calling for heat. If the voltage cuts out when the furnace goes off then you probably have a thermostat problem. Please make sure the batteries are good on your thermostat if your thermostat has batteries. Next, I would check all the safety controls, the pressure switch, limits and rollouts to make sure they are all closed when the furnace flame goes out. I know that on Goodman there is a somewhat hidden limit control that sits on the bottom of the blower housing. Please make sure this limit is checked out and not missed. I have missed seeing it before. If all of these safety controls are closed when the furnace gas goes off then I would check the gas valve. If you are getting 24 volts to the gas valve and it is not opening then this could be a gas valve problem. We have a furnace troubleshooting flow chart on the following page: I hope this will help you find the problem. God Bless you and your family. Steve Arnold

  6. Joe N October 28, 2015 at 8:42 pm #

    mine does this and has no sensor. its just a spiral ignitor with a hot surface ignitor box. Changed the spiral ignitor and still same problem. Do I change the gas valve or the HSI??

    • Steve Arnold October 29, 2015 at 6:58 am #

      Hi Joe!
      It is very unusual for a furnace to not have a flame sensing device. Please send my your furnace’s model number and I will try to look up the parts for your furnace. You would need to determine what device is causing the gas to cut off prematurely. I have seen safety devices (pressure switches, limits) cut off the gas burner’s prematurely. You would need to test with a volt meter to make sure all your safety devices are staying closed when the furnace cuts off including the thermostat connections between W and C on the control board. You should get a constant 24 to 28 volts between W and C on your control board. The hot surface ignitor should not be the problem. The purpose of the hot surface ignitor should only be to ignite the natural gas at the furnace burners. Since the gas is staying on for a short time I would think that the Gas valve is not the problem. Best of luck in finding and fixing your problem.

  7. john September 17, 2015 at 1:33 am #

    thanks for the info and the video it gave me the confidence to have a second look at the problem . sure enough it was the sensor and it was not much debris on it , a cleanup and it was fine

    • Steve Arnold September 17, 2015 at 7:13 am #

      Great! Awesome glad to hear that you were able to fix your furnace problem. Thank you so very much for taking your time to tell us the great news! Hope you have a blessed day! Steve

  8. Steve Arnold March 18, 2014 at 4:12 pm #

    This is our first blog posts. I will be happy to try and answer any questions you have. Thanks so much for your interest and support in our website! Hope you have a blessed day! Steve

Leave a Reply

© 2001 - 2014 Copyright Arnold’s service. All Rights reserved. Copy Prohibited.