Hi everyone! Having issues with my Goodman GSM9 furnace over the last week and hoping someone on here can help me. It's an intermittent issues of course, the most fun problems to solve in home care.

1. Starting last week, I was coming home from work with the furnace no longer heating the home. I would go downstairs and find the red light blinking once, indicating a lockout due to excessive retries. I could get the furnace to reliably restart by simply turning the switch off, waiting a few seconds, then turning it back on, most of the time. Other times I removed the panels and looked at loose connections, jiggled some cables, etc., and it would restart.

2. Everyone once in a while it would take multiple restarts to work. I ALWAYS get the starting fan, then the igniter. I would always HEAR the next click for gas/flames, but the behavior would vary between NO flames at all, a quick flame then the flame going out, or flames working long enough for me to retire back upstairs for a bit.

3. Just today I noticed a new behavior. The heat was off when I woke up this morning, on the weekend of course, and noticed that the red light was OFF on the control board. I flipped the heater switch off, waited, then back on, and it red light came back on solid. I watched the process: fan, igniter, click, no flames, fan spins down. No retries. I looked at the red light...and it was out!

4. So I took the panels off, checked connections again, jiggled some wires, put the panels back on, turned it back on and....the flames lit and are currently warming the house as expected.

Any ideas? So far I have checked the fuse, it's fine; I cleaned the flame sensor with steel wool.

The control board itself has been replaced before - maybe two years ago - by a heating contractor. It's new enough to have a QR code printed on it.

Thank you for ANY help!

 

Check the wires between the transformer and the board. Could be loose/corroded and when you jiggled wires it caused things to get worse.

Do you know why the board was replaced?

 

Furnace manual at:

http://www.alpinehomeair.com/related...structions.pdf

I recommend you print that off and keep a copy near your furnace.

Diagnostic codes on pages 34-35.

 

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The ignitor should turn on for thirty seconds or so to heat up. Then the circuit board should turn on the main burner gas for 3 seconds or so. IF the circuit board detects that the main burners have lit, the main burner gas should stay on.

IF the circuit board doesn't detect that the main burners have lit withing three seconds, the main burner gas should shut off and the ignition cycle should begin again with a new trial for ignition.

What you appear to be getting is unreliable main burner ignition OR the circuit board isn't detecting that the main burner is lit.

The most common cause of the main burner not being detected is a dirty flame sensor. The flame sensor is a rod sticking up into the burner flame area on the side opposite the hot surface ignitor. The flame sensor has a single wire from it going to the circuit board.

The flame sensor can get covered with invisible oxides that prevent the flames from touching the flame sensor. Take the flame sensor out and clean it with a wire brush or fine sand paper to clean off any oxides, and reinstall.

Try that first.

 

Sorry for the new guy question, but can someone point me to the transformer and wires that might be corroded? Picture or anything?

Also, I did clean the flame sensor pretty well before. I'm 99% sure this is a power issue.

 

Transformer is #27 on page 5. Connections suspect if red light goes out totally. But this is different from your #1 and #2 above.

 

Yeah the behavior of the furnace did change over the course of a week or so. I just ordered a new control board for $80 - but it won't be here until Tuesday!

 

Here are a few photos and a video of the process I am stuck in now. Not sure if this will help any.

https://www.youtube.com/watch?v=VcT_PF3O0X0

Imgur: The most awesome images on the Internet

 

Looks like you have an enhancement. That floating Tyco transformer was added and probably feeds a humidifier or something? It is possible that it may have caused problems by swinging in the breeze and pulling on wires. It should be screwed down to something but would be difficult as that model is designed to mount to an electrical box. The furnace's transformer is the GE one at the bottom.

Also - i hope you have another, much bigger, return duct on the other side of the cabinet.

 

Yeah... swinging in the breeze there.

I'm not convinced it's the control board. You'd need a meter to find out what you are losing. It could be as simple as a defective blower door switch.

The big connector on the control board is also a cause of intermittent problems. Your transformer connects to the board via the smaller floating white nylon connector. In the picture.... the red circle is the transformer. The blue circles are the gray and orange 24v wiring that needs to be followed and checked.

 

For the record, I had the exact same problem. It turned out that one of the wires on the control board had not been well soldered on, and the wire going to the gas valve had come loose. A little bit of heat and some extra solder on the solder joint on the back of the control board fixed it.

 

Unfortunately poor soldering quality is the reason for the bulk of the control board problems.