Toshiba RAS-24UKHP-ES-1 Service Manual page 42

Outer dia.
of copper pipe
∅6.35 mm
∅9.52 mm
∅12.70 mm
• Tightening torque of flare pipe connections
The operating pressure of R410A is higher than that of
R22. (Approx. 1.6 times). It is therefore necessary to
firmly tighten 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 damage to the
refrigerant cycle.
Fig. 8-5-4
Half union
Externally
threaded side
Use a wrench to secure.
Fig. 8-5-5
CAUTION
• KEEP IMPORTANT 4 POINTS FOR PIPING WORK
(1) Take away dust and moisture (Inside of the
connecting pipes.)
(2) Tight connection (between pipes and unit)
(3) Evacuate the air in the connecting pipes using
VACUUM PUMP.
(4) Check gas leak (connected points)
(Unit : N·m)
Tightening torque
16 to 18 (1.6 to 1.8 kgf·m)
30 to 42 (3.0 to 4.2 kgf·m)
50 to 62 (5.0 to 6.2 kgf·m)
Flare at indoor unit side
Flare at outdoor unit side
Flare nut
Internally
threaded side
Use a torque wrench to tighten.
8-5-3. Evacuating
After the piping has been connected to the indoor unit,
you can perform the air purge together at once.
AIR PURGE
Evacuate the air in the connecting pipes and in the
indoor unit using
a vacuum pump. Do not use the refrigerant in the
outdoor unit.
For details, see the manual of the vacuum pump.
<Using 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 oil inside of the vacuum pump
enters into the air conditioner, which use R410A,
refrigeration cycle trouble may result.)
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 the vacuum
pump.
3. Open fully the low pressure side handle of the
gauge manifold valve.
4. Operate the vacuum pump to start 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).
5. Close the low pressure side valve handle of gauge
manifold.
6. Open fully the valve stem of the packed valves
(both side 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)
Connecting pipe
Packed valve at liquid side
– 41 –
FILE NO. SVM-03009
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
Packed valve at gas side
Service port
(Valve core (Setting pin))
Fig. 8-5-6