Since yesterday morining had thermostat on 71 got up and it was 62 in the house. Messed with thermosrat and turned power off and then on it started working fine all day yesterday held tep at 72. Then today when we got up at 2:15 it was down to 68 temp in the house you can hear plower motor come on but it will not light. Red light stays on so see nothing wrong there what could it be?