Gas dryer one time burner

[Snoholoco]

My 4 yr old Kenmore dryer heats, with flame, for 1-2 minutes when cold, then cuts out. The igniter glows every couple minutes for 5-10 seconds, but the gas doesn't flow. Replaced the igniter, then the sensor....same results. I unscrewed the high temp stat on the burner cylinder, relocated it away from the flame. Same result. It all started when I leaned the dryer 45 degrees to look under it. Help?

[DIY Guy]

The dryer uses multiple thermostats to regulate the temperature. When the temperature is higher than the preset limit of a particular thermostat, the thermostat breaks the circuit and the heater goes off. When the temperature cools enough, the thermostat closes the circuit again and the heat can come on.

Most dryers have a choice of temperature settings, therefore a separate thermostat is used for each setting. The selector switch or timer control then routes the circuit through the appropriate thermostat.

If a thermostat fails, it may prevent the heat from coming on, This happens because the thermostat does not close the circuit when the temperature falls below the operating temperature of the switch. It is a simple matter to test a thermostat; it should show continuity when the switch is cool and no continuity when it is warmer than its rated temperature.

A thermostat can also fail by being always on, no matter what the temperature. This switch would show continuity whether it was hot or cold. In this case, the heater would not shut off and the the dryer could dangerously overheat. As a safety precaution a second thermostat is used, a thermal fuse. The power will be cut to the heating circuit if the maximum safe temperature is exceeded. In most cases, this is a one time fuse. The heater circuit will not function until the fuse has been replaced. Of course, it will be necessary to determine and repair the underlying cause of overheating or the fuse will just cut out again.