Mitsubishi Heavy Industries SRK25GZ-L1 Handbook page 894

FDC-HKX
(b) Refrigerant connection piping.
Connection to
left direction
(c) Connection to rear, right and front directions.
1) See page 781 to 782 for locations of connecting holes and service valves.
(4) Heat insulation
(i) There is a need to insulate both gas and liquid piping with heat insulation for protection against heat and
condensation.
1) Always use heat insulation to prevent condensation on the gas piping from becoming drain water and
causing leakage during cooling and to prevent people from being burned by the high temperature of the
surface of the gas piping as discharge gas flows through it.
2) Use heat insulation (pipe cover) on the flare connection sections of the indoor unit.
(Insulate both the gas and liquid piping.)
3) Insulate both the gas and liquid piping. Apply the insulation so that is tight against the piping and free
of gaps. Route the connecting wires with the insulation and wrap the entire bundle with exterior tape.
Wires for connecting indoor
and outdoor units
(5) Air-tight test
(a) When conducting an air-tight test of local piping, connect the piping to the check joint of the evacuating pipe connected to the
gas side service valve, and keep the service valve closed. The air-tight test pressure shall be 2.94MPa [R407C : 3.23MPa]
(b) To conduct the test, pressurize the check joint of evacuating pipe by nitrogen gas as shown below. The local piping including
indoor units can be tested as for airtightness.
Outdoor unit
892
Electric
wing
Electric
wing
Connection to
Refrigerant
front direction
piping
Gas lines
Liquid piping
Insulation
Use insulation material with good resistance heat properties (120 ˚C or more).
Gas side service valve
Check joint
Refrigerant
piping
Electric
wing
Refrigerant
piping
Connection to
lower direction
Exterior tape
Indoor unit
Indoor unit
Connection to
rear direction
Connection to
right direction