Learjet 35 PTM Chapter 11 (Air Conditioning)

Question 1

What is the altitude limitation of the Freon refrigeration system?

Answer 1

18000 ft or 35000 ft depending on compressor motor part number

Question 2

How is the flow control valve controlled?

Answer 2

Electrically via the CAB AIR switch

Question 3

How is the hot air bypass valve (H-valve) controlled?

Answer 3

Pneumatically

Question 4

If the H-valve loses servo air pressure, what position does it fail to?

Answer 4

It is spring loaded to fail to the full cold position

Question 5

What does the TEMP CONT indicator show?

Answer 5

The position of the H-valve

Question 6

Changing the COLD-HOT knob position simply changes the _______________________ on the H-valve butterfly.

Answer 6

servo air pressure

Question 7

If you turn on the cabin blower, where does it take its air from?

Answer 7

It is simply recirculating the air within the cabin and cockpit areas. The auxiliary cooler or auxiliary heater can be used to cool or heat the recirculated air.

Question 8

What is the difference between the cabin blower and the cockpit air?

Answer 8

The cabin blower comes on automatically when flipping the FAN-OFF-COOL switch to COOL and runs at maximum speed and blows air into the cabin above the divan (Same with AUX HEAT). The cabin blower knob does not effect the speed of the blower because it is always running at maximum speed.

The cockpit air is used to create airflow through the WEMAC outlets in the cockpit and cabin. If the AC is on, the cockpit fan will blow cold air through the outlets. If the AC is not on, the cockpit air simply re-circulates the air inside the cabin.

Question 9

Can the AC be powered with just the batteries on?

Answer 9

No. It needs power from a GPU or engine driven generator.

Question 10

When you move the FAN-OFF-COOL switch to COOL, what 2 things is power applied to? (What 2 things turn on?)

Answer 10

The AC compressor motor and the cabin blower motor.