Installation Manual
Page 32mrcool.com
Air Evacuation
Flare nut
Cap
Valve body
Valve stem
Fig. 6.3
Note on Adding Refrigerant
Some systems require additional charging depending on pipe lengths. The standard pipe length varies according to local 
regulations. For example, in North America, the standard pipe length is 25 ft (7.5 m). In other areas, the standard pipe 
length is 16 ft (5 m). The additional refrigerant to be charged can be calculated using the following formula:
Where 2 Zone Models N=2; 3 Zone Models N=3; 4 Zone Models N=4; 5 Zone Models N=5:
ADDITIONAL REFRIGERANT PER PIPE LENGTH
Connective 
Pipe Length (m)
Additional Refrigerant
N/A N/A
More than (Standard 
pipe length x N) ft (m) 
This - Inverter R410A: 
(Pipe length – standard length x N) x 15 g/m
(Pipe length – standard length x N)) x 0.16 oz/ft
(Pipe length – standard length x N) x 20 g/m
(Pipe length – standard length x N) x 0.21 oz/ft
This - Inverter R410A: 
(Pipe length – standard length) x 30 g/m
(Pipe length – standard length) x 0.32 oz/ft
(Pipe length – standard length x N) x 40 g/m
(Pipe length – standard length x N) x 0.42 oz/ft
Liquid Side: Ø 1/8 in (ø 6.35 mm)
Liquid Side: Ø 3/8 in (ø 9.52 mm)
 CAUTION
 DO NOT mix refrigerant types.
Fig. 6.2
Low Pressure
Main Valve
High Pressure
Main Valve
“Liquid”
High Pressure
“Suction”
Low Pressure
Wrench










