Our Lennox furnace comes on, but will not stay on when you turn it on unless you turn the thermastat up to around 80 degrees. It has a new thermastat and did it with the old one too. There is a blinking green light inside that blinks about every 2 seconds. Any ideas will help before I have to call a repairman and get ripped off. Thank you in advance, Kathy

What is the temperature in the house and what do you have the thermostat set at? Does it show either "HeatOn" or little flame showing that the thermostat is calling for heat?? Where is the green blinking light? What kind of thermostat do you have? Is this a gas or oil furnace?