{TAIL ~ The heat source controlling circuit} 42 of the heating system includes {HEAD ~ a transistor} 422, a current limiting resistor 424, a diode 425 and an oscillating circuit 423 having a variable resistor 426 
{ TAIL ~ The heat source controlling circuit } 42 of the heating system includes { HEAD ~ a transistor } 422 , a current limiting resistor 424 , a diode 425 and an oscillating circuit 423 having a variable resistor 426
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