Toshiba RAS-4M23SACV-E Installation Manual page 12

Evacuating
After the piping has been connected to the indoor unit, perform the air purge.
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 vacuum pump manual.
Use a vacuum pump
Be sure to use a vacuum pump with counter-flow prevention function so that
oil inside the pump does not flow back into the air conditioner pipes when the
pump stops. (If oil inside the vacuum pump enters the air conditioner circuit
which uses R410A, trouble with the refrigeration system may develop.)
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 begin evacuating. Perform evacuating for
about 35 minutes if the piping length is 70 meters (25 minutes for 50 total
meters) (assuming a pump capacity of 27 liters per minute). Confirm that
the compound pressure gauge reading is –101 kPa (–76 cmHg).
5. Close the low pressure 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.
CAUTION
• IMPORTANT POINTS FOR PIPING WORK
(1) Prevent dust and moisture from entering the pipes.
(2) Tighten connections carefully (between pipes and unit).
(3) Evacuate the air in the connecting pipes using a VACUUM PUMP.
(4) Check for gas leaks at all connections.
Packed valve handling precautions
• Open the valve stem until it touches the stopper. Once it is in contact with the stopper, refrain from applying any more force than is
necessary.
• Securely tighten the valve stem cap with torque in the following table:
Liquid side, gas side
(9.52 mm, 12.7 mm)
Service port
EN
33 to 42 N·m
(3.3 to 4.2 kgf·m)
14 to 18 N·m
(1.4 to 1.8 kgf·m)
Compound pressure gauge
–101 kPa (–76 cmHg)
Handle Lo
Charge hose
(For R410A only)
Packed valve at
liquid side
10
Pressure gauge
Manifold valve
Handle Hi
(Keep full closed)
Charge hose
(For R410A only)
Vacuum pump adapter for
counter-flow prevention
(For R410A only)
Service port
(Valve core (Setting pin))
Packed valve at gas side
Hexagon wrench
is required.
4 mm
Vacuum
pump