Mitsubishi Heavy Industries SRK25GZ-L1 Handbook page 37

1.5.4 Refrigerant piping
(1) Preparation
Keep the openings of the pipes covered with tapes etc. to prevent dust, sand, etc. from entering them.
Indoor unit side
(Do not
turn)
Remove
¡ Remove the flared nuts.
(on both liquid and gas sides)
(2) Connection of refrigerant piping
Indoor unit side
¡ Connect firmly gas and liquid side
pipings by Torque wrench.
Spanner
for fixing
the piping)
Torque
wrench
¡ Specified torquing value:
Liquid side (ø6.35) : 15.7~19.6N·m (1.6~2kgf·m)
Gas side (ø9.52) : 29.4~39.2N·m (3.0~4.0kgf·m)
Gas side (ø12.7) : 39.2~49.0N·m (4.0~5.0kgf·m)
¡ Always use a Torque wrench and back up spanner to tighten the flare nut.
(3) Air purge
(a) Tighten all flare nuts in the pipings both indoor and outside wall so as not to cause leak.
(b) Connect service valve, charge hose, manifold valve and vacuum pump as is illustrated below.
(c) Open manifold valve handle Lo to its full width, and perform vacuum or evacuation.
Continue the vacuum or evacuation operation for 15 minutes or more and check to see that the vacuum gauge reads – 0.1
MPa (– 76 cmHg).
(d) After completing vacuum operation, fully open service valve (Both gas and liquid sides) with hexagon headed wrench.
(e) Check for possible leakage of gas in the connection parts of both indoor and outdoor.
Stop valve
(Two-way valve)
Additional refrigerant charge
When refrigerant piping exceeds 5m(50:7m) conduct additional refrigerant charging after refrigerant sweeping.
A mount of additional charge per meter: 20 g/m
Example of additional charge amount calculation
Calculate the additional charge amount, when the piping length is 10 m.
(10 – 5) m × 20g/m = 100g
Outdoor unit side
Press
Remove
¡ Remove the flared nuts.
(on both liquid and gas sides)
Outdoor unit side
¡ Connect firmly gas and liquid side
¡ Specified torquing value:
Liquid side (ø6.35) : 15.7~19.6N·m (1.6~2kgf·m)
Gas side (ø9.52)
Gas side (ø12.7)
¡ Use one more spanner to fix the valve.
Compound
(Gauge)
–76 cm Hg
Handle Lo
(pressure)
Stop valve
(Three-way
valve)
Charge hose
Service port
100g for additional charge amount
¡ Install the removed flared nuts to the pipes to be connected,
then flare the pipes.
pipings by Torque wrench.
: 29.4~39.2N·m (3.0~4.0kgf·m)
: 39.2~49.0N·m (4.0~5.0kgf·m)
Pressure
Manifold
gauge
valve
Handle Hi
(pressure)
Charge hose
Vacuum pump
SRK-GZ
Dimension A
Liquid side
(φ6.35): 9-9.5 dia
Gas side
(φ9.52): 13.2-14 dia
(φ12.7): 16.2-17 dia
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