HOW CAN A DRYER IGNITE A FLAME AT FIRST FOR TEN MINS THEN WHEN THE DRYER WANTS TO HEAT UP AGAIN I SEE A GLOW BUT NO FLAME COMES THE SECOND TIME SHOULD I REPLACE THE THERMAL FUSE

For what it's worth: You can eliminate 3/4 of your work if you simply watch what the dryer does. Most have a peep-hole in the lower front covered by a small plastic plate. Remove the plate, start the dryer and look into the hole. If you hear a "click" right as you press the start button and the drum turns, you know the motor, timer and door switch is OK. If you then see a dull glow and a second click, ALL the thermostats, fuse-able links, gas igniter and wiring are OK. If you then see the burner ignite with the blue flame, the flame sensor, valve coils and fan are working fine. If you let it run for some time and then suddenly you only see the dull glow, but no click or blue flame, your gas valve coils are defective. (they will work when cool or cold, but not as they heat up from use) This also will stop the timer from moving since the timer runs when the coils are working well (the power to the timer comes through the coils - just figured this out today). If you don't see the dull glow, the ignition/igniter wire/element could be bad. Hope this helps folks. I see in the forums where one individual just says "Ignition coil" every time a gas dryer has a no-heat issue, but a vast majority of the problems comes from the $20.00 gas valve coils that most anyone can replace.

The key to your issue is the gas dryer. you need to know how it works to be able to diagnose it. A gas dryer will only fire up if the thermostat calls for heat and the hi limit thermostat is not tripped and the gas valves open and the igniter fires. Any of these not working will not lt dryer fire up the heat.
lets assume the running thermostat is ok since it fires up initially and they seldom are intermittent. A restricted vent would trip the high limit t-stat quickly and would not fire up again till it cools down and resets, since you have stated that the vent is clear and unrestricted we will again assume the hi limit stat is not the problem
(it still could be if it was faulty and opened up prematurely, but again that is not one of the more frequent issues). The flame detector needs to be satisfied to continue the burn after flame is ignited. The detector is a simple device that is located on the burner plenum and is a bi-metal with a clear window that lets light (flame) through to a bi-metal switch that will interrupt gas supply in case there is no flame. these again are not on the most frequent list of parts going bad.
The most likely cause of this problem is a bad igniter. they glow orange on start up and ignite the gas. even though they glow orange does not mean they are good, most develop cracks in the ceramic material and are very brittle. If a crack is present you seldom can see it and often will look normal in operation, but once heated the second cycle of heat fails to ignite. This can be measured cold by resistance check compared with standard value. I often just change them on a hunch , saves time and part cost is not high. Labor time is often higher checking it's value. Another possibility is an intermittent gas valve and that is harder to diagnose and it is an expensive part. Seldom is the valve intermittent though.
This should give you a good start, good luck

Perhaps the flame sensor is not working. If it does not sense heat, it will shut off the gas. You might go online and search for a manual to help you troubleshoot, or go to:
http://www.repairclinic.com/
for troubleshooting help and parts. I hope this is of help to you.

if the ignitor is lighting up, or if you have a actual flame pilot light, depending on the machine, if you have a pilot light, check the thermocouple that the flame from the pilot is supposed to heat , but thats on very very old machines , if you have a glow plug , ( a heat source that comes on electrically and glows , then you need to check the 2 coils that are on the gas valve, they have gone bad

The problem is the dryer coils are failing. They tend to fail as they heat up. Here is a link that should help troubleshooting a gas dryer.

Hi, If you are having problems with your gas dryer not heatingthe most common problem is that the ignitor goes bad. Even though it glowssometimes it is still not working properly. if you dryer is gas check out this gas no heat tip.... If you have an electric dryer, you can have many differentthings that can go wrong causing the dryer not to heat. check out this electric no heat tip...

heatman101

The glow coil or glow bar heats up and a sensor on the side reacts to the heat and then sends a signal to a gas valve.(solenoid valve) When the gas doesn't ignite when the coil is glowing... here are some reasons. 1. The sensor on the side of the burner assembly isn't working or sending power to the valve. 2. The valve is getting power but not opening. 3. The ignitor is not glowing hot enough to activate the flame sensor. Usually it is the sensor or the igniter not the valve.
Tom

Your gas valve coils are defective. Part #694539 and 694540 are required. Once the coils get hot they collapse internally and the gas valve shuts off. This is a common problem when valve coils get weak from use.

if the dryer doesn't shut off you need a new timer. have you replaced the igniter or glow coil? it needs to glow white not orange in order to ignite the gas.

does the igniter glow white or orange? if it is orange you need to replace it. has to be white hot to ignite. if the igniter is white it could be the coils not opening the gas valve all the time - an intermittent problem.