Toshiba RAS-077SKV-E6 Service Manual page 57

<Tightening connection>
Align the centers of the connecting pipes and tighten
the flare n ut as f ar as possib
tighten the n ut with a spanner and torque wrench as
sho wn in the figure .
Half union
Externally
threaded side
Use a wrench to secure.
Fig. 10-4-5
CAUTION
•
Do not apply excess torque.
•
Otherwise, the nut may crack depending on the
conditions.
Outer dia.
of copper pipe
∅6.35 mm
∅
9.52 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. 10-4-6
<Shaping pipes>
1. How to shape the pipes
Shape the pipes along the incused line on the
outdoor unit.
2. How to fit position of the pipes
Put the edges of the pipes to the place with a
distance of 85 mm from the incused line.
le with y our fingers . Then
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
.
10-4-4. Evacuating
After the piping has been connected to the indoor unit,
you can perform the air purge together at once.
AIR PURGE
Ev acuate the air in the connecting pipes and in the
indoor unit using a v
refr iger ant in the outdoor unit.
man ual of the v
<Using a v acuum 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 manif
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 kP a (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
-
101 kPa ( 76 cmHg)
Handle Lo
Charge hose
Connecting pipe
Packed valve at liquid side
– 56 –
FILE NO. SVM-13092
Incused line
Fig. 10-4-7
acuum pump . Do not use the
F or details
acuum pump .
Pressure gauge
Manifold valve
Handle Hi
(Keep full closed)
Charge hose
Vacuum pump
adapter for
counter-flow
prevention
Vacuum
pump
Packed valve at gas side
Service port
(Valve core (Setting pin))
Fig. 10-4-8
, see the
old valv e to