(a) In a refrigeration and air-conditioning system, what are the different methods for detecting gas leakage? (3)

(b) Name different types of detectors available and state how they are used to identify point of leakage. What safeties are observed when performing 'leak detection' (4)

(c) Explain, how leakages in the piping systems are rectified (5)

(i) temporarily

(ii) permanently?

(d) What records are to be created and maintained whilst carrying out repair/maintenance on the refrigeration system? (4)