Compressor
High pressure
switch
H.P.
Main
accumulator
Sub
accumulator
Service valve on
narrow tube
Service valve on
wide tube
CN
BN
AN
CW
BW
AW
O.D.1/4"
O.D.1/4"
O.D.1/4"
O.D.3/8"
O.D.3/8"
O.D.3/8"
Heat exchanger
Cooling cycle
Indoor unit Outdoor unit
Strainer Header
Header
M
M
M
Wide tube
Narrow tube

4. REFRIGERANT FLOW DIAGRAM

4-1. Refrigerant Flow Diagram

Outdoor Unit CU-3KS19NBU

Insulation of Refrigerant Tubing
Because capillary tubing is used in the outdoor unit, both the
wide and narrow tubes of this air conditioner become cold. To
prevent heat loss and wet floors due to dripping of
condensation, both tubes must be well insulated with a
proper insulation material. The thickness of the insulation
should be a min.5/16"(8 mm).
After a tube has been insulated,
never try to bend it into a narrow
curve because it can cause the tube
to break or crack.
Wide tube
Thickness:
Min.5/16"(8 mm)
Insulation
Narrow tube
Thickness:
Min.5/16"(8 mm)
IMPORTANT
CAUTION
Electric
expansion
valve
24