Remove eight screws (7), lockwashers (8), washers (9), and shell extension (10). Discard lockwashers.
Heat exchanger assembly shell must be tilted to allow clearance for the heat exchanger assembly air inlet
Remove heat exchanger assembly shell (6) from heat exchanger assembly (11) being careful of air inlet pipe (12).
Inspect all parts for wear, cracks, and corrosion.
Inspect all hardware for stripped or damaged threads.