23
English
NOTE
• The air-tightness test and vacuum drying should be done using the
service ports of suction gas pipe, high/low pressure gas pipe and
liquid pipe stop valve. See the [R410A] Label attached to the front
panel of the outdoor unit for details on the location of the service
port (see the figure below).
[R410A] Label
•
See 14.3. Method for adding refrigerant on page 28 for details on
handling the stop valve.
• The refrigerant charge port is connected to unit pipe. When
shipped, the unit contains the refrigerant, so use caution when at-
taching the charge hose.
<Air tight test>
Pressurize the suction gas pipe, high/low pressure gas pipe and liquid
pipe from the service ports of each stop valve to 550 psi (3.8 MPa) (do
not pressurize more than 550 psi (3.8 MPa)). If the pressure does not
drop within 24 hours, the system passes the test.
If there is a pressure drop, check for leaks, make repairs and perform
the air tight test again.
<Vacuum drying>
Evacuate the system from the suction gas pipe, high/low pressure gas
pipe and liquid pipe stop valve service ports by using a vacuum pump
for more than 2 hours and bring the system to 500 microns or less.
After keeping the system under that condition for more than 1 hour,
check if the vacuum gauge rises or not. If it rises, the system may
either contain moisture inside or have leaks.
NOTE
During the rainy season, moisture might enter the piping. If
working during a rainy season and the work takes long enough
for condensation to form inside the pipes, take the following
precautions:
After evacuating the system for 2 hours, pressurize the system to
375,000 microns (vacuum break) with nitrogen gas and evacuate the
system again using the vacuum pump for 1 hour to 500 microns or
less (vacuum drying).
If the system cannot be evacuated to 500 microns within 2 hours,
repeat the operation of vacuum break and vacuum drying.
Then, after leaving the system in a vacuum for 1 hour, confirm that the
vacuum gauge does not rise.
11. Pipe insulation
NOTE
Pipe insulation thickness provided below are guidelines only. Pipes
must be insulated with the appropriate thickness of insulation per ap
-
plicable local/state or national codes.
•
Insulation of pipes should be done after performing 10. Air tight test
and vacuum drying on page 22.
• Always insulate the suction gas pipe, high/low pressure gas pipe,
liquid pipe and pipe connections.
•
Failing to insulate the pipes may cause leaking or burns.
Be sure to use insulation designed for HVAC equipment.
• Reinforce the insulation on the refrigerant piping according to the
installation environment. Condensation might form on the surface of
the insulation. Refer to the below.
-
Ambient temperature : 86°F (30°C), humidity : 75% to 80% RH :
minimum thickness : 9/16 in. (15 mm).
-
If the ambient temperature exceeds 86°F (30°C) and the humidity
80% RH, then the minimum thickness is 3/4 in. (20 mm).
See the Engineering Data Book for detail.
•
If there is a possibility that condensation on the stop valve might
drip down into the indoor unit through gaps in the insulation and
piping because the outdoor unit is located higher than the indoor
unit, this must be prevented by caulking the connections. (Refer to
the following figure.)
3
4
5
1
6
1
2
1
Insulation material
2
Caulking, etc.
3 Liquid pipe stop valve
4 Suction gas pipe stop
valve
5 High/low pressure gas
pipe stop valve
6
Connection pipe
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2023/05/29 10:20:16
2023/05/29 10:20:16
