On modulating burners...
Whirpool/Kenmore stopped using these around 1970. I think there are two main reasons:
1) Cost. This hydraulic system is a lot more expensive than a bimetallic disc thermostat; and,
2) The reality that you don't need a lot of choices or control over the drying cycle: this system doesn't require user input, decisions or that you set any knobs. At a time when specmanship and more choices & knobs must be better, one setting that does it all couldn't possibly work. (Said tongue-in-cheek).
Whirpool/Kenmore stopped using these around 1970. I think there are two main reasons:
1) Cost. This hydraulic system is a lot more expensive than a bimetallic disc thermostat; and,
2) The reality that you don't need a lot of choices or control over the drying cycle: this system doesn't require user input, decisions or that you set any knobs. At a time when specmanship and more choices & knobs must be better, one setting that does it all couldn't possibly work. (Said tongue-in-cheek).