I have a Whitfield Profile 20 FS-2 pellet stove about 3 years old which has been great. Over the last couple of months, it seems to be running through a 40 pound bag of pellets faster and faster. We only use the low setting which is suppose to be 1.5 lb/hr. The start of the heating season we were getting over 24 hours to a bag, now we are burning through a bag in about 18 hours. In the manual it states a couple of places to call a service tech to if you need to adjust the feed trim. On older models it seems the feed trim was on the control pad, but not with this model. Is this something I can do myself?