A family members dryer isn't heating after the first few minutes. After checking it out I notice that it initially fires up and lasts for quite a few minutes. At some point the flame stops (i assume this is normal). After a few minutes I see the ignitor glowing red, the gas comes out and lights up. The ignitor starts to dim down. Then roughly 10 seconds of having a flame, I hear a click and the flame goes out. After a few minutes of it being off, it will fire up and stay on for a few minutes, but after the initial flame goes out and it attempts to fire up again, the flame dies only seconds after it ignites. I tried doing continuity testing on everything and they check OK from a room temperature reading. Can anyone give me any ideas which parts I should be looking at? Thanks in advance.

I replaced the coils but still have the same symptoms. Venting also appears to be fine. Nothing in the unit or the vent pipe that I can see. Outside appears to have good air flow.

Any other ideas?