I have a Armstrong Ultra SX80. The blower motor stays on all the time. I have never had a problem with this unit. I have had it for about 20 years. When I open the control panel it shuts off like it should. Any ideas? Thanks

Are you getting any flashes from the control board diagnostic light? Do the burners ever ignite? If the burners never ignite, and the blower is running constantly, it sounds like you have an open high limit.

Thanks for the answer but had to get somebody out there to get it fixed. It was the wires coming out of the furnace to the box. Rubbed its way through and caused a short. Thanks again for your answer.

Just glad you got it fixed. Thanks for the update.