I have an 88 Resolute Acclaim, Model 0041, cast iron. I bought it two years ago from someone who claimed they only burned it a few times. Last year I burned it hard and after the season I had to replace with arch inserts. This year, It appears I am having to replace the upper firebricks, lower firebricks and the combustion package. All 3 units are warped and currently when I burn, it will burn very hot because of the added airflow. What is causing this to warp? The parts to replace will be over $350. Does it make sense to replace the parts or to part it out?