Mitsubishi Heavy Industries SRK25GZ-L1 Handbook page 211

(2) Connection
Indoor
Liquid side
Gas side
¡ Secure the nut with a specified tightening
torque to avoid any gas leaks.
¡
Specified tightening torques are as follows:
Liquid side (ø 6.35): 17mm in width across flat of the flare nut: 15.7-19.6 N·m (1.6-2.0 kgf·m)
Gas side (ø 9.52): 22mm in width across flat of the flare nut: 29.4-39.2 N·m (3.0-4.0 kgf·m)
Gas side (ø 12.7): 24mm in width across flat of the flare nut: 39.2-49.0 N·m (4.0-5.0 kgf·m)
(3) Air purging
To protect the global environment, use a vacuum pump that do not release flourocarbon gas into the atmosphere.
When a vacuum pump cannot be used due to certain conditions for installation, sufficient refrigerant is available for air
purging with refrigerant for the outdoor unit.
Note: Fully open the service valves (on both liquid and gas sides) after completing air purging
(a) Remove the cap on both gas and liquid sides before starting operation.
(b) After completing the operation, do not forget to tighten the cap (gas may leak).
(c) Conduct air purging for all connected indoor units.
Procedure
1 Secure all flare nuts on both indoor and outdoor sides to prevent leaks from
the pipes.
2 Connect the service valves, charge hose, manifold valve and vacuum pump
as shown in the right figure.
3 Fully open the handle Lo for the manifold valve, and pump a vacuum for 15
minutes. Ensure that the meter is indicating -0.1 MPa (-76cmHg).
4 After vacuuming, fully open the operational valve (both liquid and gas sides)
with a hexagon wrench.
5 Ensure that there are no gas leaks from the joints in the indoor and outdoor
units.
6 Repeat the above steps 1 ~ 5 for all connected indoor units.
(4) Additional refrigerant charge
(a) When the total refrigerant pipe length for all the rooms exceeds the length of the uncharged pipe (20m), additional refrigerant
is required.
(If 20m or less, additional charge is not required.)
(b) For this multi type room air conditioner, it is not necessary to charge the refrigerant for the total maximum length in all the
rooms.
Model
SCM452HENG-L
SCM452CENG-L
(c) Ensure that there are no gas leaks from the pipe joints by using a leak detector or soap water.
Outdoor
Liquid side
¡ Secure the nut with a specified tightening
torque to avoid any gas leaks.
Charged pipe length
(Amount of uncharged
refrigerant) *1
1300g
*1: Charge amount at the time of shipment.
Gas side
¡ When air purging with a vacuum pump,
secure the nut with a specified tightening
torque to avoid any gas leaks.
¡ When air purging with a refrigerant from
an outdoor unit, just temporarily secure the
nut.
Charge hose
Maximum total pipe length for all rooms
On site additional charge
20g/m
SCM-HG (2 room)
Compound Pressure
pressure gauge
gauge
Manifold
valve
-0.1 MPa
(-76cmHg)
Handle Hi
Handle Lo
Charge hose
Vacuum pump
Open
Open
(Maximum amount of refrigerant)
1500g
209