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Air Conditioning and Refrigeration IV 2010 Question Paper For CBSE Class XII Exams

Air Conditioning and Refrigeration IV

1. Briefly describe the following : (4�2 Marks)
   (a) Package unit
   (b) Heating and humidifying equipment
2. Why are ducts used in an air-conditioning system ? List the factors due to which pressure of air falls in a duct. (8 Marks)
3. Differentiate control system. Give examples of both types of elements.(8 Marks)
4. Describe the functions and working of a modulating motor. (8 Marks)
5. List various electrical faults, usually found in a domestic refrigerator.(8 Marks)
6. Explain the procedure of charging through suction line, with the help of a neat diagram.( 8 Marks)  

7. Describe the working of the following : (4�2 Marks)
   (a) Compressor
   (b) Relays
8. Write short notes on any two of the following : (4�2 Marks)
   (i) Bypass control
   (ii) Safety switches
   (iii) Pressure testing
   (iv) Cooling coil