Toshiba RAS-3M26S3AV-E Service Manual page 55

10-2-6. Refrigerant Piping Connection
CAUTION
KEEP IMPORTANT 4 POINTS FOR PIPING WORK
1. Keep dust and moisture from entering the 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)
Flaring
1. Cut the pipe with a pipe cutter.
OK
90˚
Fig. 10-2-10
2. Insert a flare nut into the pipe, and flare the
pipe. As the flaring sizes of R410A differ from
those of refrigerant R22, the flare tools newly
manufactured for R410A are recommended.
However, the conventional tools can be used by
adjusting projection margin of the copper pipe.
• Projection margin in flaring :
B (Unit : mm)
Rigid (Clutch type)
R410A tool used
Outer dia. of
copper pipe
R410A
6.35 0 to 0.5 (Same as left)
9.52 0 to 0.5 (Same as left)
12.7 0 to 0.5 (Same as left)
Imperial (Wing nut type)
Outer dia. of copper pipe
6.35
9.52
12.7
• Flaring size : A (Unit : mm)
Outer dia. of copper pipe
6.35
9.52
12.7
∗ In the case of flaring for R410A with the conventional
flare tool, pull out it approx. 0.5 mm more than that
for R22 to adjust to the specified flare size.
The copper pipe gauge is useful for adjusting
projection margin size.
NO GOOD
Obliquity Roughness
Fig. 10-2-11
Conventional tool used
R22 R410A R22
1.0 to 1.5 0.5 to 1.0
1.0 to 1.5 0.5 to 1.0
1.0 to 1.5 0.5 to 1.0
R410A R22
1.5 to 2.0 1.0 to 1.5
1.5 to 2.0 1.0 to 1.5
2.0 to 2.5 1.5 to 2.0
A
Fig. 10-2-12
A
+0
- 0.4
R410A R22
9.1 9.0
13.2 13.0
16.6 16.2
10-2-7. 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
conditioner when the pump stops.
(If inside oil of the vacuum pump enters into the air
conditioner which adopts R410A, a trouble of the
Warp
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 40 minutes if the
piping length is total 70 meters.
(assuming a pump capacity of 27 liters per minute.)
B
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)
Service port
(Valve core
(Setting pin))
Packed valve
at gas side
- 55 -
FILE NO. SVM-15074
Pressure gauge
Manifold valve
Handle Hi
(Keep full closed)
Charge hose
(For R410A only)
Packed valve Vacuum pump
at liquid side adapter for
counter-flow prevention
(For R410A only)
Vacuum pump
Fig. 10-2-13