Won't ignite The Goodman furnace GMS80905CNA won't light, it goes thru the 3 attempts but then shuts off I cleaned the flame sensor altho there is no flame. The motor starts up & about 25 seconds the glow plug comes on but for only about 5 to 10 seconds. It was installed about 4 yrs ago, and has worked fine. My wife says it has been doing the 2 & 3 start ups for a few weeks but it has always started the burners.

Clean your flame sensor first before you change that gas valve

check to see that your condensate line is not plugged. next check the p-trap where your line goes in. also check your flue abs flue pipe see as it comes out of roof is it open or does it have an elbow coming off of it i usually install with elbow preferably less water goes in the units resevoir hope that helps u

Hello,sounds like you have a dirty flame sensor. This is a metal rod on the oppositenside of the hot surface ignitor. turn off power to the furnace and remove the flame sensor, then use steel wool and clean the flame sensor and reinstall. Next turn back power to Furnace.

Problem: Your furnace will not ignite the gas to produce heat for your home. When a furnace has a bad igniter what I see most of the time is the following sequence of operation:


1. Thermostat calls for heat.
2. Draft inducer motor starts.
3. Pressure switch attached by a small plastic or rubber tube senses the negative pressure produced by the draft inducer and closes.
4. Draft inducer runs for 30 seconds to a minute before you hear a gas hissing sound. The ignitor did not glow, the flame sensor (a small metal probe about 1/8" in diameter, with a white porcelain base) does not sense the flame, so after 8 to 10 seconds the hissing sounds stops with no ignition of gas to heat your home. Your furnace shuts down and goes into a lock out condition until you turn your power switch back off and on again. Then the sequence starts all over again with no ignition of the gas.
Solution: You probably need to purchase and install a new igniter. I would suggest that you inspect your igniter closely for cracks. Make sure you do not touch the igniter with your bare hands. If you do not visually see a crack, then you could have a furnace control board problem or a limit, roll-out switch problem. The furnace's control board might not be supplying the voltage to the ignitor. If your furnace lights and the gas stays on for 8 to 10 seconds, then shuts right back off, then you need to clean your flame sensor with light sand paper or steel wool. You might need a new flame sensor, but most of the time they can be cleaned an will work well after cleaning.

NATE, NCCER, PHCC,HVAC Certified Instructor

Sounds as though your issue lies within the flame sensor.

The flame sensor senses that there is flame present once there is a call for heat. It sends its signal back the board or ICM and the furnace operates as normal. If no signal is sent, then the furnace automatically shuts down as a safety procedure. The furnace will attempt to light several times before shutting down on a fault code or lockout.


The number 1 reason for flame sensors to fail is they are dirty. Check the sensor for dirt build-up. Clean the sensor with a damp rag or a scratch pad. Inspect the grommets for crackings. Also check and clean all grounds. If this doesn't work, you will need to replace the sensor or call for a service technician to ensure the sensor is the only issue at hand.

In the burner compartment opposite of the ignitor is the flame sensor. seems to be dirty. one screw holds it in. Remove and clean with a wire brush.

First when it goes out again, locate the furnace and look thru a small viewing port to see if there is a light blinking, count the number of blinks. Then look at the wiring diagram for a diagnostic code chart. This will give you a strart of where to look.

Sounds like you may have a weak or bad flame sensor. If the circuit board does not sense a good flame it will not light the burners. Also if your furnace is 5 yrs or newer it should give you a fault on circuit board in the form of a blinking or a code itself.

After the gas turns on, it is the flame sensor's job to see that ignition took place and send 24v to the gas valve. If it does not do this, the gas valve shuts down as a safety precaution. After 3 tries, the furnace will go into "lockout" and will not let it attempt to start again. The lockout can be resolved by turning off the power to the furnace for a couple minutes and then turning it back on. Sounds like the real problem is a faulty flame sensor not sending 24v to the gas valve. Sometimes they can be cleaned with a piece of sandcloth. This will cure failure to recognize the flame due to carbon build up on the sensor. Otherwise, the sensor will need to be replaced. Hope this helps!

try cleaning the burners and or adjust the distance the igniter is from the actual burner .