8
Evacuating
After the piping has been connected to all indoor
unit(s), you can perform the air purge together at once.
AIR PURGE
Evacuate the air in the connecting pipes and in the
indoor unit using vacuum pump.
Do not use the refrigerant in the outdoor unit.
For details, see the manual of vacuum pump.
Use a vacuum pump
Be sure to use a vacuum pump with counter-flow
prevention function so that inside oil of the pump does
not flow backward into pipes of the air conditioner when
the pump stops. (If inside oil of the vacuum pump
enters into the air conditioner which adopts R410A, a
trouble of the refrigeration cycle may be caused.)
1. Connect the charge hose from the manifold valve to
the service port of the gas side packed valve.
2. Connect the charge hose to the port of vacuum pump.
3. Open fully the low pressure side handle of the gauge
manifold valve.
4. Operate the vacuum pump to start for evacuating.
Perform evacuating for about 35 minutes if the piping
length is total 70 meters.
(25 minutes for total 50 meters)
(assuming a pump capacity of 27 liters per minute.)
Then confirm that the compound pressure gauge
reading is –101 kPa ( –76 cmHg).
5. Close the low pressure side valve handle of gauge
manifold.
6. Open fully the valve stem of the packed valves (both
sides of Gas and Liquid).
7. Remove the charging hose from the service port.
8. Securely tighten the caps on the packed valves.
Packed valve handling precautions
• Open the valve stem all the way out ; do not try to
open it beyond the stopper.
• Securely tighten the valve stem cap in torque as follows:
Tightening connection
Align the centers of the connecting pipes and tighten
the flare nut as far as possible with your fingers. Then
tighten the nut with a spanner and torque wrench as
shown in the figure.
CAUTION
• Do not apply excess torque. Otherwise, the nut
may crack depending on the conditions.
(Unit : N·m)
Outer dia. of copper pipe
Tightening torque
Ø6.35 mm
14 to 18 (1.4 to 1.8 kgf•m)
Ø9.52 mm
33 to 42 (3.3 to 4.2 kgf•m)
Ø12.7 mm
50 to 62 (5.0 to 6.2 kgf•m)
• Tightening torque of flare pipe connections
Pressure of R410A becomes higher than that of R22.
(Approx. 1.6 times) Therefore, using a torque wrench,
tighten firmly the flare pipe connecting sections which
connect the indoor and outdoor
units up to the specified
tightening torque.
Incorrect connections may
cause not only a gas leakage,
but also a trouble of the
refrigeration cycle.
Half union
Flare nut
Externally
threaded side
Internally
threaded side
Use a wrench to secure.
Use a torque wrench to tighten.
Flare at
indoor
unit side
Flare at
outdoor
unit side
Outdoor
unit
Indoor unit
4M27 only
D
D UNIT
Ø6.35
Ø9.52
A
A UNIT
Ø6.35
Ø12.7
C
C UNIT
Ø6.35
Ø9.52
B
B UNIT
Ø6.35
Ø9.52
Compound pressure gauge
Pressure gauge
Manifold valve
Handle Hi
(Keep full closed)
Charge hose
(For R410A only)
Vacuum pump adapter
for counter-flow prevention
(For R410A only)
Packed valve at gas side
Service port
(Valve core (Setting pin))
Handle Lo
Charge hose
(For R410A only)
–101kPa (–76cmHg)
Vacuum
pump
Packed valve
at liquid side
3M26
4M27
Connectable capacity class
A
B
C
D
Total
10, 13
16
16
——
(with reducer) (with expander) (with expander)
45
16
10, 13
10, 13
——
10, 13
16
16
16
(with reducer) (with expander) (with expander) (with expander)
52
16
10, 13
10, 13
10, 13
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