Heater element ignites, but turns off before gas begins flowing which stops the process.
I actually have a GMT070-3A model Goodman furnace, but my guess is that it's somewhat similar to this one regarding this problem.
What happens inconsistently is that the heating element lights up when the unit is getting ready to start heating (blower has been running about 10 seconds or so and continues fine through all of this), but the element turns off prior to the point where the gas starts to be emitted. And of course, whatever sensor is in there won't supply gas without a hot element. If this cycles 3 times, I have to turn the power off to the unit before it will try again (another 3 times if need be -- usually starts up during the second go around).
Again, this problem is inconsistent. And the heating element works, just turns off sooner than it should at times. Not sure what's causing this or what to check/replace.
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Check if 24 volts is being sent from the board to the gas valve, if not the board is nad and will need to be replaced, if there is 24 volts at the gas vlave terminals then the gas valve must be replaced.
Do you see the actual ignitor glow? You must be saying that you sanded the sensor. The ignitor, after the little inducer fan comes on will begin to glow a bright orange until the burner lights. If the ignitor is broken, you will NOT see a glow, and you may smell a faint smell of gas.
Check your furnace by the electrical panel, there should be a blinking error light. Sometimes there is a legend to how many blinking lights means what. I had an issue with mine, read the code and it turns out it was hitting the high heat limit. Turns out my blower motor wasn't turning on. Replaced it with a spare and it was fixed. Find out what type of furnace, and google the name, model, and the words, 3 blinking lights. Does your furnace turn on at all? Does it start to go through the cycle then stop? This is the proper cycle of a furnace and what should happen.
Inducer motor kicks on, it runs for a little bit, about 3-5 seconds, then you should see a bright yellow glow, this is the igniter, shortly after, you should hear a click and the gas should start to flow, almost immediately it turns to a blue flame. Then your igniter should turn off and the blower motor start up.
Be sure that that PVC vent pipe going outside is not plugged or trapped with water. If the vent pressure switch is not tripping the furnace will not ignite. Also be sure that you don't have a gas leak somewhere causing weak gas flow to furnace.
Fan purge for 30-45 seconds. During this time, a pressure switch is actuated by the running of the purge fan, proving the control board the purge fan is running.
After purge and purge prove, the hot surface ignition and or spark begins. After a few second delay, the gas valve will open. The control board then monitors for flame prove through another sensor located near the burners. If there is no flame within 3-5 seconds, the gas valve closes. It will repeat this process, usually 3 times, before it shuts the system down, which requires a power down of the system to reset.
I have seen trash get into the hose between the purge blower and the purge switch. But you could be having other problems.
Your main limit switch is activated. Maybe for good reason. This switch keeps the furnace from overheating. I have the same problem right now and I think my a/c coil may be blocked, limiting air flow through the heat exchanger and the furnace. Does your gas and main circulating fan come on for a few minutes before the switch activates and the light begins blinking?
Check your furnace filter and any return air ducts in your home - see if they are blocked or restricted.
Check the roll out switch(s) and the lock out switches. They are a small disc looking about the size of a nickle, with with 2 wires attached on them. There will be a re-set button in the middle that resembles a small peg. Push this in to re-set. As the glow coil shorted out, the fuse on the control board may have blown. On the newer furnaces find the main board and look for a car type fuse. If blown, replace. You also have the symptoms of a bad limit switch, by the clicking noise (the heat fan relay) and the blower fan running instantlly.