lowering the power level applied to the heating means to the next lower power level upon detecting {HEAD ~ a rate} of change exceeding the reference rate and raising the power level applied to the heating means to the next higher power level upon subsequent detection of {TAIL ~ a rate} of change less than the reference rate 
lowering the power level applied to the heating means to the next lower power level upon detecting { HEAD ~ a rate } of change exceeding the reference rate and raising the power level applied to the heating means to the next higher power level upon subsequent detection of { TAIL ~ a rate } of change less than the reference rate
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH