DC Inverter Multi VRF System 
20 
 
pipe valve of the outdoor unit. If required amount cannot be quickly filled due to pressure increase 
of the pipe, then set the unit in cooling startup and fill refrigerant from the low pressure check valve 
of the outdoor unit.   
(3) Calculation example 
 
Fig. 27 
IDU 
Liquid pipe: 
Total length of each liquid pipe 
Φ9.52:A+B+C+a=10+105+5+3=23m 
Φ6.35: D+b+c+d=5+3+2+1=11m 
Therefore, the minimum quantity of additional refrigerant = 23×0.054+11×0.022=1.264kg 
4.5 Electric Wiring 
4.5.1 Notices for Wiring 
(1) Install units according to national wiring codes. 
(2) Use air conditioner specialized power supply and make sure that it is consistent with 
system’s rated voltage. 
(3) Do not pull the power cord with force. 
(4) All electrical installation must be performed by qualified technicians in accordance with 
local laws, regulations and this user manual. 
(5) Caliber of the power cord must be large enough. A damaged power cord or connection 
wire must be replaced by specialized electrical cords. 
(6) If the supply cord is damaged, it must be replaced by the manufacturer or its service 
agent or a similarly qualified person in order to avoid a hazard; 
(7) A  circuit breaker  having a  contact separation of  at  least  3mm in  all  poles should be 
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