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
Flare at
indoor
up to the specified tightening torque.
unit side
Incorrect connections may cause not
only a gas leakage, but also a trouble
of the refrigeration cycle.
Half union
Flare nut
Flare at
Externally
Internally
outdoor
threaded side
threaded side
unit side
Use a wrench
Use a torque wrench
Fig. 9-3-4
to secure.
to secure.
Fig. 9-3-5
9-3-3. 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 15 minutes if the piping
length is 20 meters. (15 minutes for 20 meters)
(assuming a pump capacity of 27 liters per minute.)
Then confirm that the compound pressure gauge
reading is –101 kPa ( –76 cmHg).
Compound
Pressure gauge
5. Close the low pressure side
pressure
gauge
valve handle of gauge manifold.
-101kPa
Manifold valve
(-76cmHg)
6. Open fully the valve stem of
Handle Hi
Handle Lo
(Keep full closed)
the packed valves (both side
Charge hose
Charge hose
of Gas and Liquid).
(For R410A only)
(For R410A only)
Vacuum pump
7. Remove the charging hose
adapter for
counter-flow
from the service port.
Connecting
prevention
pipe
(For R410A only)
8. Securely tighten the caps
on the packed valves.
Vacuum
pump
Packed valve at liquid side
Packed valve at gas side
Service port
Fig. 9-3-6
(Valve core (Setting pin))