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Appropriate tightening torque:
Outside
diameter of
Cap (N·m)
Shaft (N·m)
copper pipe
(mm)
ø9.52
15
ø12.7
20
ø15.88
25
ø19.05
25
ø25.4
25
Caution:
•
Keep the valve closed until the refrigerant charging is ¿ nished.
Opening the valve before charging the refrigerant may cause damage
to the unit.
•
Do not use a leak detection additive.
Airtight test procedure
(1) After obtaining to the design pressure (4.15 MPa) using nitrogen gas, allow the system
to stand for about one day. If the pressure does not drop, airtightness is good.
However, if the pressure drops, and the leakage area is unknown, the following bubble
test may also be performed.
(2) After the pressurization described above, spray the À are connection parts, brazed
parts, and other potential leakage areas with a bubbling agent (KyuboÀ ex, etc.) and
visually check for bubbles.
(3) After the airtight test, wipe off the bubbling agent.
Caution:
Only use R410A refrigerant.
- Using other refrigerants such as R22 or R407C, which contains chlorine,
will deteriorate the refrigerating machine oil or cause the compressor to
malfunction.
2 Evacuation
Evacuate with the valve of the heat source unit closed and evacuate both
the connection piping and the indoor unit from the service port provided on
the valve of the heat source unit using a vacuum pump. (Always evacuate
from the service port of both the high-pressure pipe and the low-pressure
pipe.) After the vacuum reaches 650 Pa [abs], evacuate for at least one hour
or more. Then, stop the vacuum pump and leave it for 1 hour. Ensure the
degree of vacuum has not increased. (If the degree of vacuum increase is
larger than 130 Pa, water might present. Apply pressure to dry nitrogen
gas up to 0.05 MPa and vacuum again.) Finally, seal in with the liquid
refrigerant through the high-pressure pipe, and adjust the low-pressure
piping to obtain an appropriate amount of the refrigerant for operation.
* Never perform air purging with refrigerant.
[Fig. 10.3.2] (P.9)
A System analyzer
B Low knob
D Valve (heat source
E Low-pressure pipe
unit)
G Service port
H Three-way joint
J Valve
K R410A cylinder
M Vacuum pump
N To indoor unit
Size of
hexagonal
Service port
wrench
(N·m)
(mm)
6
4
9
4
15
6
12
30
8
30
8
C High knob
F High-pressure pipe
I Valve
L Scale
O Heat source unit
10.3. Airtight test, evacuation, and
refrigerant charging
1 Airtight test
Perform with the valve of the heat source unit closed, charging the
refrigerant pressurize the connection piping and the indoor unit from the
service port provided on the valve of the heat source unit. (Always pressurize
from both the high-pressure pipe and the low-pressure pipe service ports.)
[Fig. 10.3.1] (P.9)
A Nitrogen gas
B To indoor unit
D Low knob
E High knob
G Low-pressure pipe
H High-pressure pipe
J Service port
Observe the following restrictions when conducting the air tightness test
to prevent negative effects on the refrigerating machine oil. Also, with
nonazeotropic refrigerant (R410A), gas leakage causes the refrigerant
composition to change and affects performance. Therefore, conduct the
airtightness test cautiously.
•
If a À ammable gas or air (oxygen) is used as the pressurization
gas, it may catch ¿ re or explode.
Note:
•
Always add the appropriate amount of refrigerant. Also always charge
the system with liquid refrigerant.
•
Use a gauge manifold, charging hose, and other parts for the
refrigerant indicated on the unit.
•
Use a graviometer. (One that can measure down to 0.1 kg.)
•
Use a vacuum pump with a reverse À ow check valve.
(Recommended vacuum gauge: ROBINAIR 14830A Thermistor Vacuum
Gauge)
Also use a vacuum gauge that reaches 65 Pa [abs] or below after
operating for ¿ ve minutes.
3 Refrigerant Charging
Because the refrigerant used with the unit is nonazerotropic, it must be
charged in the liquid state. Consequently, when charging the unit with
refrigerant from a cylinder, if the cylinder does not have a siphon pipe,
charge the liquid refrigerant by turning the cylinder upside-down as shown in
Fig.10.3.3. If the cylinder has a siphon pipe like that shown in the picture on
Fig.10.3.3, the liquid refrigerant can be charged with the cylinder standing
upright. Follow the cylinder speci¿ cations carefully. If the unit should
accidentally be charged with gas refrigerant, replace all the refrigerant with
new refrigerant. Do not use the refrigerant remaining in the cylinder.
[Fig. 10.3.3] (P.9)
A Siphon pipe
B If the R410A cylinder does not have a siphon pipe.
C System analyzer
F Valve
I Heat source unit
Restriction
23
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