i have a 25-pdvc dated 7/03. what setting should i use to get the longest hrs of burn out of 40lbs, if i have the heat set at 1 and the blower at 2-3? i dont need alot of heat where im using it, i just want to get the most hrs out of a bag of pellets. also, how many hrs should i get? right now i have it set at 1-2-1 and get about 19hrs. thanks