Cooling Pipe And Drain Pipe - Mitsubishi Electric PLH-2 Installation Manual

6.4. Refrigerant piping
1) Indoor unit
• This unit has the flared connections on both indoor and outdoor sides.
1.1. When using separetely purchased refrigerant pipes:
a) Piping connection procedures
See that stop valve on outdoor unit is fully shut (unit is shipped with
valve shut). Remove caps from piping and unit and make flare con-
nection promptly (within five minutes). Repeat for each connection,
one at a time.
Removing caps and leaving piping open for extended periods of time
can permit penetration of damaging dust, moisture or foreign matter
into unit. In such cases, use refrigerant (R-22) to air purge piping
before making connections with unit.
b) Precautions concerning flexible tubing
• Use flexible tubing for indoor piping connections only.
• Avoid bending at angles more acute than 90°. Avoid repeated
bending of same tube more that three times.
• Locate bends as near as possible to center of piping lengths and
make bend with as large of a bending radius as possible.
B
H
C
J
I
A
D
C
E
G
F
K

6. Cooling pipe and drain pipe

E
6.4. Refrigerant piping
1.2. When using commercially available copper pipes:
See that stop valve on outdoor unit is fully shut (unit is shipped with
valve shut). After all piping connections between indoor and outdoor
unit have been completed, vaccuum-purge air from system through
the service port for the stop valve on the outdoor unit.
After completing procedures 1.1. or 1.2. above, open outdoor unit
stop valves stem fully. This completes connection of refrigerant cir-
cuit between indoor and outdoor units. Stop valve instructions are
marked on outdoor unit.
• Apply thin layer of refrigerant oil to pipe and joint seating surface
before tightening flare nut.
• Use two wrenches to tighten piping connections.
• Air-purge the refrigerant piping using your own refrigerant gas (don't
air-purge the refrigerant charged in the outdoor unit).
• Use leak detector or soapy water to check for gas leaks after con-
nections are completed.
• Use refrigerant piping insulation provided to insulate indoor unit con-
nections. Insulate carefully following shown below.
6.4. Refrigerant piping
1.3. Heat insulation for refrigerant pipes
A Refrigerant pipe and insulating material (must be supplied locally)
B Remove the electric wiring service panel.
C Pipe cover
D Gas pipe
E Liquid pipe
F Band
G Press the pipe cover against the unit's outer surface.
H Cross-sectional view of connection
I Refrigerant pipe
J Insulating material for refrigerant pipe
K Squeeze
C
F
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