IN ITEMS 4-20 THROUGH 4-26, SELECT FROM COLUMN B THE COMPONENT THAT IS RESPONSIBLE FOR THE FUNCTION LISTED IN COLUMN A. COMPONENTS IN COLUMN B MAY BE USED MORE THAN ONCE. A. Functioms 4-20. Cools hot engine bleed air 4-21. Cools air on the same principle that a car radiator cools water 4-22. Controls flow of bleed air to primary heat exchanger ejectors 4-23. Uses the electri- cal signals from the avionics temperature flow sensor B. Components 1. Primary ejector valve 2. Primary heat exchanger 3. Avionics RAM air servo 4. Flow modulating system pressure regulator valve 4-24. Protects the refrigeration turbine from heat damage during overtemperature conditions 4-25. Monitors the differential pressure of the bleeder air up and downstream of the flow modulating system pressure regulator valve 4-26. Ensures that a sufficient amount of cooling air goes to the avionics systems 24 4-27. When an overtemperature exists in the turbine or compressor section of the refrigeration turbine/ compressor assembly, the protec- tive temperature sensors will cause which of the following conditions to occur? 1. The sensor sensing the over- temperature will close the flow maculating system pressure regulator and cause turbine speed to decrease 2. The sensor sensing the over- temperature will close the engine bleed-air pressure regulation and shutoff valve on the engine producing the overtemperature 3. The sensor sensing the over- temperature will close the engine bleed-air check valve on the engine producing the overtemperature 4. The compressor temperature sensor closes the flow modulating system pressure regulator and the turbine temperature sensor closes the affected engine bleed-air check-valve