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Tim H.
Tim H., HVAC Professional
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Goodman Furnace Ignites and Shuts Off After A Few Seconds

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Hello, my goodman furnace ignites and shuts off after a few seconds. I researched it and thought it was the flame sensor. I replaced the flame sensor but it still does the same thing

Thanks for giving me the opportunity to help! Can I get full model number of the furnace? Are you saying the burners ignite, then shut down? Are you getting an LED flash code off the board when it shuts down?

Customer: replied 3 years ago.

I did see a red light flashing on the board but I am not sure if it was blinking before, during or after shutdown. Model number is ***** M P 1 2 5 - 5 the light is solid red when trying to turn on. it ignighted three times then stopped trying then the light started blinking, i thought i should count the number of light blinks to figure out the code you were looking for. i got up to 67 blinks and quit. i think it will just keep blinking

Did the burners ever light, if not briefly?
Customer: replied 3 years ago.

yes, they stay on for about ten seconds

I would try cleaning your flame sensor. This is a flame "rod" that sits in by the burners and may look similar to this. Take it out (one screw) and "shine it up" with some steel wool or emery cloth, then replace.
Customer: replied 3 years ago.

from the research i did already, i thought that was the problem, i already did that and that did not work, so i went and bought a new one and replaced it. i still have the same problem.

Is the burner flame hitting the flame sensor? Good ground from the burners to the board?
Customer: replied 3 years ago.

yes the flame hits. what do you mean about good ground?

The flame sensor works on flame rectification which requires a good ground between the burner area and the board. Make sure the furnace is grounded to house wiring coming into it and that there is no corrosion on the ground wires. You may have to run a separate ground wire from the board to the burner area.

If this grounding doesn't do it, you need to replace the furnace board. This furnace is getting older and you are not getting the proper flash code for ignition problems, but, rather rapid blinking. It is not unusual for these boards to go bad after many years.

One other thing I'd try before replacing board is to turn furnace power off, run a jumper piece of wire between the R and W terminals on the board and turn back on. See if problem still occurs. We are basically just eliminating the thermostat as a possible source of the problem here. If problem still occurs with new flame sensor, R-W jumpered, good grounding---it points to a bad circuit board.

Customer: replied 3 years ago.

I am going to go and try the jumper cable. so you think if that jumper cable keeps it on then I have a bad thermostat? You had mentioned above about the blinking light being rapid. it was not rapid it was very slow. i stood there for about 5minutes counting to 67, which is why I gave up. I took some pictures to send you but the chain link is not highlighted

Yeah, I'm not showing that as a flash code which is why I suspect the board. A Goodman GMP should have a 1,2,3,4, or 5 blink code or just On (continuous) or a rapid flashing, not a slow flashing. In other words on a 1 blink code, it will flash, then there will be a pause, then flash, then a pause and so forth. Same with the 2,3,4, and 5 blink codes.

Customer: replied 3 years ago.

ok something very weird is happening. i did the jumper and the same thing happened. then when it shut down the light stopped blinking after 4or 5 times, i didnt count because i was not expecting it to stop. so i started the process over to count the lights but this time it only blinked once. so i started over again and now itseems to be working. very crazy. i wonder if i should keep my morning appointment? what are your thoughts?I

Yeah, it's up to you. You could have a variety of problems. Possibly a stat that is starting to act up. Possibly a bad board. When furnaces get older like this, many things can occur.
Customer: replied 3 years ago.

as of right now the system is still running. i think you were right it is probably a bad board, i am going to keep my appointment tomorrow. at least now i know he won't be able to take advantage of me and try to sell me a new system. before he comes i am going to call the hvac supply store and price the part.

These boards are not very expensive, around $79. So don't let him charge you too much if that's what he decides to do. We can keep the question open for a while, if you want. Keep in touch and let me know what happens.

Customer: replied 3 years ago.

Hi Tim,

I just wanted to say thanks again for all of your help yesterday. The technician came out this morning and confirmed it was the board. He said they would charge me $528 to replace it, I called the HVAC supply store and the said the part is in stock and is $87.00. I am going to replace it my self. I am going to purchase the part and hold on to it until I have the problem again. It has been working with no problem since last night. I just have one last question. when I bought the flame sensor it was slightly different from the original one. If the board is slightly different and I have a question about wiring it, if I need to open up a new case is there anyway I can somehow request you to help me with the situation?

Yes, you can request me specifically. Good luck!
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