Blower kicks on for a short time and then kicks off. It cycles repeatly, is it possibly hysterisis of the thermostat setting or furnance related? The model of our unit is: Intertherm Model 911030.

It operates normally when there is a large differential between the temperature and thermostat setting. When the thermostat setting is close, then it will cycle.

Set the heat anticipator on the thermostat to the amp rating stamped on the gas valve. Or simply move it a little more toward the arrow that says longer inside the thermostat, I'm assuming this is not a digital stat.

I am sorry I didn't mention it is a digital Magic Stat. I transferred the wires from the merc. switch t-stat screw for screw as per the instructions, but the wire colors do not match the labels on the digital stat screws. It is possible that it was hooked up incorrectly to begin with. The system functions fine in all other aspects.

I am unfamiliar with that stat. do the instructions let you set it for number of cycles per hour or anything?

I don't want to but in but it could be the flame sensor needs cleaning or replacing.