(a) Sketch and describe a high pressure cut-out in a refrigeration system. (5)

(b) The refrigeration compressor has stopped due to operation of the h. p. cut-out. Explain

(i) The possible causes. (3)

(ii) How these causes would be found and possible remedies. (3)

(c) What steps are taken if the compressor "short-cycle" on low pressure cut-out? (5)