Fan dancing

[HKestenholz]

Use a fan center relay to power the fans independently of the furnace controls, close the relay from a fan ampere sensing relay when the fan motor runs, a common item to run humidifiers. A bit of fancy thinking required, but no strain to other controls.

http://www.climatedoctors.com/items/item.aspx?itemid=429448

http://www.heatpro.us energy businessmen’s knowledge

Yes, you really have to find out the MAKE and MODEL to get good answers. There IS more than one machine made.