V6-i VRF 50/60Hz 
    43 
6 Protection Control 
6.1 High Pressure Protection Control 
This  control  protects  the  system  from  abnormally  high  pressure  and  protects  the  compressors  from  transient  spikes  in 
pressure. 
Figure 3-6.1: High pressure protection control 
Notes:   
1.  P
c
: Discharge pressure 
 
6.2 Low Pressure Protection Control 
This  control  protects  the  system  from  abnormally  low  pressure  and  protects  the  compressors  from  transient  drops  in 
pressure. 
Figure 3-6.2: Low pressure protection control 
Notes:   
1.  P
e
: Suction pressure 
 
6.3 Discharge Temperature Protection Control 
This  control  protects  the  compressors  from  abnormally  high  temperatures  and  transient  spikes  in  temperature.  It  is 
performed for each compressor. 
Figure 3-6.3: Discharge temperature protection control 
When the discharge temperature rises above 120°C the system displays P4 protection and all units stop running. When P4 
protection occurs 3 times in 100 minutes, the H6 error is displayed. When an H6 error occurs, a manual system restart is 
required before the system can resume operation. 
   
 
 
When  P2  protection  occurs  3  times 
in  60  minutes,  the  H5  error  is 
displayed. When an H5 error occurs, 
a  manual  system  restart  is  required 
before  the  system  can  resume 
operation. 
High pressure protection, error code P1 is displayed 
Low pressure protection, error code P2 is displayed