9.4.2.15 The cooling operation or heating operation does not operate. 
 Check of 4-way, please refer to part 5 in 9.5 Trouble Criterion Of Main Parts. 
 
9.4.2.16  When cooling, heat exchanger of non-operating indoor unit frosts. 
 When heating, non-operating indoor unit get warm. 
●  EXV faulty 
●  Wire and tubing connected in reverse. 
Check of EXV, please refer to part 6 in 9.5 Trouble Criterion Of Main Parts.