Toshiba RAS-4M23SAV-E Service Manual page 75

• Tightening torque of flare pipe
The pressure of R410A is higher than R22.
(Approx. 1.6 times) Therefore securely tighten the
flare pipes which connect the outdoor unit and
indoor unit with the specified tightening torque
using a torque wrench.
If any flare pipe is incorrectly connected, it may
cause not only a gas leakage but also
trouble in the refrigeration cycle.
Fig. 10-4-9
Half union
Externally
threaded side
Use a wrench to secure.
Fig. 10-4-10
D
C
B
A
Outdoor unit
Fig. 10-4-11
Connectable capacity class
A B
16 16
(with expander)
4M23
10, 13 10, 13
Flare at
indoor
unit side
Flare at
outdoor
unit side
Flare nut
Internally
threaded side
Use a torque wrench to tighten.
6.35
D UNIT
9.52
6.35
C UNIT
9.52
6.35
B UNIT
9.52
6.35
A UNIT
9.52
Indoor unit
C D Total
16 16
10, 13 10, 13
10-4-7. 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 condi-
tioner 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 20 minutes if the
piping length is total 40 meters. (30 minutes for
total 60 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.
Compound pressure gauge
–101kPa (–76cmHg)
Handle Lo
Charge hose
(For R410A only)
Packed valve
at liquid side
46
– 75 –
Pressure gauge
Manifold valve
Handle Hi
(Keep full closed)
Charge hose
(For R410A only)
Vacuum pump adapter
for counter-flow prevention
(For R410A only)
Vacuum
pump
Service port
(Valve core (Setting pin))
Packed valve at gas side
Fig. 10-4-12