Normally when a dryer starts to exhibit longer dry times, then suddenly stop working, it is an indication that the Thermal Cut-Out has blown. The TCO acts as a fuse for the heating element circuits. When an overheat condition occurs, normally the hi-limit thermostat will open to shut off the heating element. This is how the dryer regualtes its heat. However, if the hi-limit thermostat malfunctions, the TCO will blow, It is not resettable, and has to be replaced. This also means that the hi-limit thermostat could be suspect and it should also be replaced at the same time. Normally, when you go to replace one or the other they are sold as a set. This still does not rule out the possibility of a bad heating element, either.
However, you said the dryer additionally does not start. With a blown TCO or heating element the dryer will still run, but will not heat. I'll get back to this in a minute...
Now...if your dryer has been having problems drying, the first thing you need to check is the ventilation ducting to ensure that it is not kinked or clogged. Poor air flow is the number one cause of dryer failures. Not to mention it can cause fires due to lint backing up inside the dryer. This could be the "electrical" smell you've experienced. If trapped lint is ending up on the heating element it will smolder and burn. I recommend the ducting be cleaned thoroughly about once per season. That's 4 times per year. If you've never cleaned the ducting, or your dryer is pushed all the way up against the wall causing the ducting to become kinked, you will have air flow problems. One way in determing air flow is to remove the vent hose from the back of the dryer and start the unit (of course, you need a working dryer in order to do this). The air should be forceful and slowly warm up to about 140 degrees. If the air flow is weak, you may have a clog inside the air baffle of the dryer (this is where the lint screen slides into). If the air flow is good, reattach the dryer hose and check at the output of the dryer vent as it exits your home. If the air flow is weak or non-existent then you know you have a clog in the vent line somewhere. Periodic cleaning will go a long way towards preventing future clogs. Dryer vent rule of thumb: The SHORTER and STRAIGHTER the vent line, the BETTER. Everywhere you have a bend or kink is an area where you will create potential collection points for lint.
Now, in determing which component is bad in your dryer. If your dryer has the lint screen on top of the unit, you will need to remove the back panel to get to the heating circuits. If your dryer has the lint screen in the door, you will need to remove the lower kick panel under the door by pushing in on the release tabs with a putty knife. They are located along the front seam about two inches in from each side.
The heating circuit is set up and troubleshot as follows:
Heating Element (located inside the heater box) - Resistance reading should be 9-13 ohms.
Thermal Cut-Out (located on the heater box) - Resistance reading of 0 ohms.
Hi limit Thermostat (located on the heater box closest to the heating element leads) - Resistance reading of 0 ohms.
Operating Thermostat (located on the air baffle) - (May have 4 wires attached to it). Will read 0 ohms across one set of leads, 7 ohms across the other.
*Thermal Fuse (located on the air baffle) - Resistance reading of 0 ohms.
*If the Thermal Fuse blows, this will shut down the entire dryer. This is your likely suspect.
Here's a few things that will cause a dryer not to start at all:
1. Broken Drum Belt - If dryer is equipped with a broken belt relay, this will shut the dryer down.
2. Broken Door Switch - If the door switch is broken, this will shut down the entire dryer as no power is applied to the start switch with the door switch open.
3. Bad Start Switch - If the start switch does not toggle close or stay closed when released, the dryer will not start.
4. Bad Timer - If the timer does not function the dryer will not start.
5. Bad Drive Motor - No Motor, drum does not rotate, heating circuits may or may not function. DOUBLE CHECK the CONNECTOR PLUG on the Drive Motor. I have found situations where this plug came loose for whatever reason and caused the dryer to either shut off completely or work intermittently.
6. Bad A/C Receptacle and/or Connector Plug - If you aren't getting the proper voltage to the dryer, it will not run.
I just threw in those other items to give you some other things to consider. Troubleshooting is always an exact science as symptoms don't always indicate what you think the problem could be. The reason I keyed in on the heating circuitry was the intial symptoms you started with. Longer dry times are usually associated with poor air flow which usually causes something to eventually blow. I hope you find this information helpful. Please post back with any comments that I may assist you further. I hope this isn't confusing to you. Please ask for clarification if it is.
on Nov 18, 2017