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1. Nitrogen gas pressurization
(1) Connect the testing tools.
• Make sure the stop valves are closed and do not open them.
• Add pressure to the refrigerant lines through the service port of the liquid stop valve.
(2) Do not add pressure to the specified pressure all at once; add pressure little by little.
1 Pressurize to 0.5 MPa (5 kgf/cm
not decrease.
2 Pressurize to 1.5 MPa (15 kgf/cm
not decrease.
3 Pressurize to 2.94 MPa (29.4 kgf/cm
refrigerant pressure.
(3) If the specified pressure holds for about one day and does not decrease, the pipes have
passed the test and there are no leaks.
• If the surrounding temperature changes by 1 °C, the pressure will change by about
2
0.01 MPa (0.1 kgf/cm
G). Make the necessary corrections.
(4) If the pressure decreases in steps (2) or (3), there is a gas leak. Look for the source of the gas
leak.
2 Evacuation
Evacuate with the ball valve of the outdoor unit closed and evacuate both the
connection piping and the indoor unit from the service port provided on the ball
valve of the outdoor unit using a vacuum pump. (Always evacuate from the
service port of both the liquid pipe and the gas pipe.) After the vacuum reaches
650 Pa [abs], continue evacuation for at least one hour or more.
* Never perform air purging using refrigerant.
[Fig. 8.3.2] (P.4)
A System analyzer
B Lo Knob
D Ball valve
E Liquid pipe
G Service port
H Three-way joint
J Valve
K Cylinder
M Vacuum pump
Note:
•
Always add an appropriate amount of refrigerant. Also always seal the
system with liquid refrigerant. Too much or too little refrigerant will cause
trouble.
•
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.)
3 Refrigerant Charging (For R407C models)
Since 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 syphon pipe, charge the liquid refriger-
ant by turning the cylinder upside-down as shown below. If the cylinder has a
syphon pipe like that shown in the figure at the right, the liquid refrigerant can
be charged with the cylinder standing upright. Therefore, give careful attention
to the cylinder specifications. If the unit should be charged with gas refrigerant,
replace all the refrigerant with new refrigerant. Do not use the refrigerant re-
maining in the cylinder.
[Fig. 8.3.3] (P.4)
Airtight test procedure
2
G), wait five minutes, and make sure the pressure does
2
G), wait five minutes, and make sure the pressure does
2
G) and measure the surrounding temperature and
C Hi Knob
F Gas pipe
I Valve
L Scale
• If a flammable gas or air (oxygen) is used as the pressurization
gas, it may catch fire or explode.
• Do not use a refrigerant other than that indicated on the unit.
• Sealing with gas from a cylinder will cause the composition of
the refrigerant in the cylinder to change.
• Use a pressure gauge, charge box, and other parts especially
for R407C.
• An electric leak detector for R22 cannot detect leaks of R407C.
• Do not use a haloid torch. (Leaks cannot be detected.)
8.4. Thermal insulation of refrigerant piping
Be sure to give insulation work to refrigerant piping by covering liquid pipe and gas
pipe separately with enough thickness heat-resistant polyethylene, so that no gap
is observed in the joint between indoor unit and insulating material, and insulating
materials themselves. When insulation work is insufficient, there is a possibility of
condensation drip, etc. Pay special attention to insulation work to ceiling plenum.
[Fig. 8.4.1] (P.5)
A Steel wire
C Asphaltic oily mastic or asphalt
E Outer covering B
Heat
Glass fiber + Steel wire
insulation
Adhesive + Heat - resistant polyethylene foam + Adhesive tape
material A
Indoor
Vinyl tape
Outer
Floor exposed
Water-proof hemp cloth + Bronze asphalt
covering B
Water-proof hemp cloth + Zinc plate + Oily
Outdoor
paint
Note:
•
When using polyethylene cover as covering material, asphalt roofing shall
not be required.
•
No heat insulation must be provided for electric wires.
[Fig. 8.4.2] (P.5)
A Liquid pipe
B Gas pipe
D Finishing tape
E Insulater
[Fig. 8.4.3] (P.5)
Penetrations
[Fig. 8.4.4] (P.5)
<A> Inner wall (concealed)
<C> Outer wall (exposed)
<E> Roof pipe shaft
<F> Penetrating portion on fire limit and boundary wall
A Sleeve
C Lagging
E Band
G Sleeve with edge
I Mortar or other incombustible caulking
J Incombustible heat insulation material
When filling a gap with mortar, cover the penetration part with steel plate so that
the insulation material will not be caved in. For this part, use incombustible materi-
als for both insulation and covering. (Vinyl covering should not be used.)
Restriction
B Piping
D Heat insulation material A
C Electric wire
<B> Outer wall
<D> Floor (fireproofing)
B Heat insulating material
D Caulking material
F Waterproofing laye
H Lagging material
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