My dryer no longer advances on Auto-Dry cycle. When I set the timer to a timed drying cycle, it works fine. The timer advances for 60 min. and shuts off. The heater element should be fine, because I recently repaired a melted wire to the heating element. I've also checked the vents and they are clear. Is this the thermostat I need to purchase if I find that the current thermostat shows no continuity? Is this thermostat the same as an "internal bias" thermostat? Thank you.
Answer Bickabah, Yes, the 307249 regulating thermostat is the thermostat you'd need to check first. It does have an "internal bias heater" that should have a resistance of 2400ohms resistance (across the two small, brass colored terminals in the center. It is also a SPDT(single throw, double pole) switch. when the temperature is below 150 degrees the circuit travels across the two lower terminals across from each other and the heater circuit is completed. When the temperature is reached the thermo disc "opens" and the circuit "switches" between the common lower terminal and the upper terminal on the dual side, this supplies 120 VAC to the timer motor and advances the timer until the thermostat resets and starts the heat cycle again. If you're sure the vent and hood are clean and clear, no kinks etc. and the thermostat checks correctly, You'll need to check for a "weak" hi limit switch 303396 or an air leak in the drum seals or blower assembly.
When using dryer in auto dry or perm press mode, timer won't shut off on it's own .Dryer dries fine. On fluff dry, timer will advance and shut off on it's own, but it also is heating in fluff dry mode. Shouldn't fluff dry, be operating without heat?
Is it a bad timer, or a bad cycling thermostat?
Answer Jim, Your first check should be the heating element Y313538 or Y308612 (depending on serial number) if it is shorted or grounded it will continue to heat on all settings, including air fluff, and this could cause the dryer timer to not advance in the auto cycles. The dryer has to heat properly in order for the timer to advance.
How do I test the Multi-Temp Cycling Thermostat with Internal Bias Heater?
Answer Hello Norman. The two large terminals on the thermostat 307249 should read closed for continuity and the two small should show an ohms resistance value. You can test this with a multi-meter TJMA-DMT3. Here is a link on how to use a multi-meter. http://forum.appliancepartspros.com/oven-repair-including-ranges-cooktops/4810-how-check-continuity-ohmmeter.html