Flame goes out within a minute - Whirlpool LGN2000LWH Gas Dryer

Hello. You likely need to replace the gas valve safety coils. You can do one of 2 things. You can purchase a voltohm meter for under 20 dollars, or you can start replacing components within the burner assembly until you find the problem. The valve is very reliable and rarely fails. One of the most common parts that need replacing in the burner assembly is the valve solenoids.
If you choose to purchase one for testing purposes, I'm posting a link now that will show you exactly how to use it. Dont be intimidated by it (you might already know how to use one, but I dont know that). Here is the helpful video. It's easier to see than explain in words.
http://applianceassistant.com/safety/how_to_use_a_volt_meter.php
http://www.appliancepartspros.com/partsearch/model.aspx?model_id=5133609&diagram_id=28278866#d28278866 LGN2000LW0---zero*

http://www.appliancepartspros.com/partsearch/model.aspx?model_id=5133609 LGN2000LW1

Here is a helpful link on disassembling your dryer.
http://applianceassistant.com/videos/appliance_repair/whirlpool_dryer/index.php


Your dryer will have a cap on the lower left side of the front cabinet. This is a viewing port for observing the burner assembly. I also did a parts search with that model number and found 2 close matches. You will need to look at these links, and then decide with your model number which one is yours. They will help you determing where all of the parts are located within your dryer and burner assembly.

IF THE IGNITOR GLOWS, you know that it's okay, you also know that the thermal fuse in the back of the dryer is okay.
NEXT, you'll want to see if it turns OFF. If it didnt I'll cover that later. If the ignitor clicks off after a few seconds of glowing bright orange, You know that the flame switch mounted to the left of the burner tube is OKAY as well.
At the moment the click of the flame switch is observed, the burner valve should release gas for burner ignition. If the ignitor turns off with no ignition, and you are positive you're getting gas supply to the dryer, you likely will have to replace the two coil valve solenoids on the top of the burner.
The two safety coils may gradually fail over weeks, or even months giving longer dry times and only partial heating. As safety coils are failing, they'll work fine for only a short amount of time, and then after about 30 minutes of cycling on and off to maintain the drum's temperature, they will break down and cease to open the valve leaving you with cool or wet clothing at the end of the cycle.

IF THE IGNITOR GLOWS, BUT NEVER CLICKS OFF you likely have a bad flame switch (flame sensor).

Here are some helpful links for part replacement in the burner assembly; You will unplug the dryer before any continuity testing or unit disassembly. If you test for continuity on a live circuit, that poses a big risk to you and it will fry your meter.
http://www.youtube.com/user/RepairClinic#p/search/1/tMqublMvau0 Flame sensor replacement. To test the flame sensor (located on the burner tube), unplug the wire connector, and put the voltohm meter test leads to the 2 prongs and test for continuity. If it has continuity, it's okay.

http://www.youtube.com/user/RepairClinic#p/search/0/Mj7Q-SexmGQ Gas valve solenoid replacement video.

http://www.youtube.com/watch?v=iK9q6K7iIrQ&feature=mfu_in_order&list=UL Ignitor replacement video. You test the ignitor the same way as the flame switch. Disconnect the plug, and test for continuity on the 2 prongs (the ignitor side of the connector). Continuity means it's good.

I hope that you found this helpful, and that you can solve your problem with it. I will be happy to help you further if you need any assistance. Let me know if you need help, or you get your problem solved. It really makes my day to help someone out.

Thanks,

Mike