Two month old Guardian gas furnace blower continues to run and will not shut off. Flashing code says Rollover switch open. Problem began when the furnace started properly, the gas kicked on and I lowered the thermostat to shut off the furnace and opened the windows to heat the house. The blower never shut off even though the burner did. I had to turn off the electric to the furnace to shut off the blower. Warranty ? or does someone have a fix? Thanks