Out to perform annual heating maintenance. Amana split system attic. Duct work is falling apart. Duct work in really bad shape, past the point of repair, need to replace. Went thru furnace and checked parts. Electrical looks ok. Control board not burnt spots. Cleaned burners and flame sensor. Checked variable speed motor. Ok starting to get dusty. See pictures. Hot surface ignitor ok. Checked system safety features. System working as it should. Washed filter, dried and re installed. Problem is you have a high efficiency unit, with bad duct work.. loosing efficiency. 13 supplies and 2 returns. Emailed quote for replacement of duct work