Evacuating - Toshiba RAS-25 Series Installation Manual

Tightening connection
Align the centers of the connecting pipes and tighten the fl are nut as far as pos-
sible with your fi ngers. Then tighten the nut with a spanner and torque wrench
as shown in the fi gure.
Half union
Externally
threaded side
Use a wrench to secure.
CAUTION
Do not apply excess torque. Otherwise, the nut may crack depending on
the conditions.
Outer dia. of copper pipe
Ø6.35 mm
Ø9.52 mm
Tightening torque of fl are pipe connections
The operating pressure of R32 is
higher than that of R22 (approx.
1.6 times). It is therefore necessary
to fi rmly tighten the fl are pipe
connecting sections (which connect
the indoor and outdoor units) up to the
specifi ed tightening torque. Incorrect
connections may cause not only a
gas leakage, but also damage to the
refrigeration cycle.

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-fl ow prevention function so that
inside oil of the pump does not fl ow backward into pipes of the air conditioner
when the pump stops.
(If oil inside of the vacuum pump enters the air conditioner, which use R32,
refrigeration cycle trouble may result.)
1. Connect the charge hose from the manifold valve to the service port of the
packed valve at gas side.
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 confi rm that the
compound pressure gauge reading is –101 kPa (–76 cmHg).
5. Close the low pressure side valve handle of the gauge manifold valve.
6. Open fully the valve stem of the packed valves (both gas and liquid sides).
7. Remove the charging hose from the service port.
8. Securely tighten the caps on the packed valves.
1118350136_(01_EN).indd 10 1118350136_(01_EN).indd 10
Flare nut
Internally
threaded side
Use a torque wrench to tighten.
(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)
Flare at
indoor unit side
Flare at
outdoor unit side
Compound pressure gauge
–101 kPa
(–76 cmHg)
Handle Lo
Charge hose
Connecting pipe
Packed valve at gas side
Service port (Valve core (Setting pin))
Packed valve at liquid side
CAUTION
KEEP IMPORTANT 5 POINTS FOR PIPING WORK.
(1) Take away dust and moisture (inside of the connecting pipes).
(2) Tighten the connections (between pipes and unit).
(3) Evacuate the air in the connecting pipes using a VACUUM PUMP.
(4) Check gas leak (connected points).
(5) Be sure to fully open the packed valves before operation.
Packed valve handling precautions
Open the valve stem all the way out, but do not try to open it beyond the
stopper.
Pipe size of Packed Valve
12.70 mm and smallers
1 5 8 . 8 m m
Securely tighten the valve cap with torque in the following table:
Cap Cap Size (H)
H17 - H19
Valve Rod Cap
H22 - H30
Service Port Cap
Service Port Cap
Valve Rod Cap
10
Pressure gauge
Manifold valve
Handle Hi
(Keep full closed)
Charge hose
Vacuum pump adapter for
counter-fl ow prevention
Vacuum
pump
Size of Hexagon wrench
A = 4 mm
A = 5 m m
Torque
14~18 N·m
(1.4 to 1.8 kgf·m)
33~42 N·m
(3.3 to 4.2 kgf·m)
8~12 N·m
H14
(0.8 to 1.2 kgf·m)
14~18 N·m
H17
(1.4 to 1.8 kgf·m)
Hexagon wrench
is required.
A
H
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