3 Troubleshooting for Mode Selection Box 
3.1 Warning 
 
 
3.2 E2: Communication error between MS and master outdoor unit 
 Digital display output 
 
 Description 
  Communication failure between MS and master outdoor unit. 
  All units stop running. 
  Error code is displayed on the malfunction MS box.   
  The indoor unit display board or wired controller connected to this MS displays "F8”. 
 
 Trigger / recover condition 
  Trigger condition: MS and master outdoor units cannot communication for 1 minutes after the system power on. 
  Recover condition: Communication go back to normal. 
  Reset method: Resume automatically. 
 
 Possible causes 
  Communication wires between MS and outdoor units not connected properly. 
  Loosened wiring within electric control box. 
  The sequence of the PQE signal lines is incorrect. 
  Interference from high voltage wires or other sources of electromagnetic radiation. 
  Communication wire too long. 
  Damaged outdoor or MS PCB or electric control box communication terminals block. 
 
 
   
 All  electrical  work must    be    carried    out    by  competent    and  suitably    qualified,    certified    and   
accredited  professionals  and  in  accordance  with  all  applicable  legislation  (all  national,  local  and  other  laws, 
standards, codes, rules, regulations and other legislation that apply in a given situation). 
Power-off the MS unit before connecting or  disconnecting any connections or wiring, otherwise electric shock 
(which can cause physical injury or death) may occur or damage to components may occur.