On rare occasions, our longsuffering and much-repaired Kenmore clothes dryer will sometimes not fully dry a load, as if the heater didn’t turn on. Setting the temperature selector to High:
Then resetting the cycle timer to the spot marked with the otherwise unlabeled asterisk to activate the humidity sensor gets the job done:
We normally crank the knob to the asterisk, leave the temperature set to Normal, and mostly it works.
After perusing the wiring diagram:
I thought perhaps the temperature selector had become intermittent, along the lines of the temperature control knob on the oven, so I turned off the breaker, verified the dryer was disconnected, and popped the top:
It turns out that part is no longer available from any of the usual sources; one describes their inventory as both “used” and “out of stock”; if it’s dead, a resurrection will be in order.
The selector knob has three positions:
- Low = 0 Ω, as in a closed switch
- Medium = 5.8 kΩ, most likely a fixed resistor
- High = open circuit, as in an open switch
The Low and High positions meet the limits shown in the diagram and Medium falls in between, so it seems to be working as designed. If it intermittently fails as a short, then the clothes would get Low heat and (I think) would emerge somewhat more dry than we notice.
I put it all back together, but we won’t know for a while if my laying-on-of-hands non-repair had any effect.
One terrifying possibility, which we reject out of hand, is that we occasionally forget to crank the cycle knob around to the asterisk before punching the Start button. That would explain all the observed facts and contradict none, but is inconceivable.
The Smell of Molten Projects in the Morning 