Samson Boiler Draft Controller

[digger104]

I have installed a Samson draft Control on my tassco Boiler, which I trying to burn coal, The instruction are not very clear, I have tried different setting, It seams that the control is not really doing much, not much movement at all, Can some one explain how this control is suppose to work and how the setting work, I'm using the horizontal settings which are the red numbers, The numbers are like 40-50-60-70-80-90-100, what does these numbers represent, 140 or 150 in degrees. Example- I set the number at 80 and I have the aquastat set to turn on the circ. at 180 and I have 20 deg. diff. The boiler will heat up to 200 and the draft control is pretty much the same but the aquastat does keep it in the 160 to 200 range. Should I not see more moverment with the draft. Also can I set the draft number back at night to maintain a boiler temp like 170 and still hold the fire, I can take the chain off and close the draft all the way and I still have a fire in the morning after 12 hrs. but the temp. has dropped to around 150. I was thinking if this works like I think I should be able to turn the draft control back with out unhooking the chain and completly closing the draft, and maintain a higher water temp. but I do realize I will have to bank with more coal to make it last till morning. Thanks for your help.