Iding Rate Box

I'm trying to understand what my idle rate box actually does on my Susquehanna furnace. It just has a knob with adjustments of min and max, with some tick-marks in between. I believe there's a sticker on the side of the unit stating that it's a % timer. The range is from 60-600 seconds. I'm not sure what I'm adjusting. Is it the off time, or the on time or both together?

Min might be OFF time and MAX might be ON Time. Like this Attached?

If they are Rheostat as stated, they probably some type of a speed control....

I light my Intermatic Timer on my Keystoker, you just put in a certain number of pins in every 10 mins for 'ON' Time of 15-20 secs per pin approx. I think I have 4-5 (1-1.5 mins) every 10 mins.

The control box is actually different. They never updated the manual. The box just feeds at max rate intermittently vs. the rheostat adjusting the actual rate. The unit has no rheostats at all now. It's just max feed, with only a carpet stroke adjustment as well as this idle rate box. I think it always runs for the same time, but you adjust the "off" time. I'm not positive though.

Ah, figures. It could be just an OFF time adjustment? Not sure. I don;t think a lot of people have those type of stoves or controls. Sorry.