s a spring-loaded door to supply air to the heat exchanger in the event the inlet is blocked. Bleed air is routed through the heat exchanger and directed onto the turbine wheel. The turbine wheel and impeller are connected to a common shaft. The rotation of the impeller draws air through the inlet and over the heat exchanger coils. Air passing over the heat exchanger coils cools the bleed air. A sump housing assembly contains oil to lubricate the turbine wheel and impeller bearings.SERVICINGHEATINGNo regularly scheduled maintenance is required on the hot air mixing valve. The operation of the valve may be checked by placing the mode control in AUTO and moving the auto temperature control from COLD to HOT. The mixing valves should move near full travel with a smooth steady motion. Watch each valve for evidence of hang up or jerky movement.COOLINGThe cooling system is to be check every 200 hours, or at recommended inspection intervals, inspect the turbine for security of installation. Check the hoses and lines attached to the turbine for condition a...