– 71 –
Fig. 10-5-10
10-5-4. 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.
Fig. 10-5-11
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
into 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 15 minutes if the
piping length is 20 meters
(15 minutes for 20 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.
9. Perform steps 1 through 8 above on each con-
nected indoor unit.
CAUTION
• IMPORTANT POINTS FOR PIPING WORK
1. Keep 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.
∗
1 When connecting a capacity class 16 pipe to the
indoor unit, attach the expander which is avail-
able as an optional accessory to the 9.52 mm
diameter packed valve of the outdoor unit.
Outdoor unit
Indoor unit
Unit A
Unit B
Ø9.52
Ø6.35
Ø9.52
Ø6.35
Service port
(Valve core (Setting pin))
Compound pressure gauge
–101 kPa (–76 cmHg)
Handle Lo
Charge hose
(For R410A only)
Charge hose
(For R410A only)
Connecting pipe
Pressure gauge
Manifold valve
Handle Hi
(Keep full closed)
Vacuum pump adapter for
counter-flow prevention
(For R410A only)
Vacuum
pump
Packed valve at liquid side
Packed valve at gas side
M14
M18
Connectable capacity class
A
B
Total
10, 13
10, 13
23
10, 13, 16
∗
1
10, 13, 16
∗
1
26
