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Removing charge hose after refrigerant replenishment
(1) Close both liquid and gas shutoff valves, loosen the nut of the
charge hose a little with a spanner, and check that no gas comes
out.
(2) Remove the charge hose.
(3) Apply PAG oil to the seal, and hold and screw in the nut by hand.
(4) Further tighten the nut with a spanner by 30° to 45°.
(5) Check that there is no refrigerant gas leakage from the nut and
plug. If there is any refrigerant gas leakage, further tighten them.
<Opening or closing state on completion of
refrigerant replenishment>
Inside equipment
Outside equipment
(onsite piping side)
WARNING
• Fully open the stop valve and disconnect the charge hose
from the service port on completion of refrigerant replen-
ishment.
• High-pressure refrigerant will be discharged because there is no
valve core, which will result in a very dangerous state.
8-4 Air tight test and vacuum drying method
After finished piping work, carry out air tight test and vacuum drying.
Inspection system
Refer to the following connection diagram and connect the nitrogen
bottle, refrigerant bottle, and vacuum pump to the outdoor unit.
Gauge manifold
Charge
hose
Meter
Nitrogen
Vacuum pump
R744 tank (with siphon)
Method of airtight test
Keep applying a maximum pressure of 12.3 MPa from both liquid and
gas pipes (and make sure that the pressure will not exceed 12.3
MPa). The air conditioner will pass the test if there is no pressure fall
for 24 hours. If there is a pressure fall, make a leakage check, remedy
the problem, and conduct an airtight test again.
Method of vacuum drying
• Evacuate the system from the liquid and gas pipes by using a vac-
uum pump for more than 2 hours and bring the system to
–100.7 kPa or less. After keeping the system under that condition
for more than 1 hour, check that the vacuum gauge does not rise.
If it rises, the system may either contain moisture inside or have
leaks.
12
Plug
Nut of service port
Seal
Service port
Liquid side
shutoff valve
Gas side
Outdoor unit
shutoff valve
Shutoff valve
service port
Valve A
Valve B
:Field pipings
• Take the following procedure if the air conditioner is installed in
the rainy season, if dew condensation in the pipe is feared
because the period of installation work is long, or if the penetra-
tion of moisture including rainwater is feared during the period of
installation work.
(1) After performing the vacuum drying for two hours, pressurize
to 0.05 MPa (i.e., vacuum breakdown) with nitrogen gas, then
evacuate the system to –100.7 kPa for an hour using the vac-
uum pump (vacuum drying).
(2) If the pressure does not reach –100.7 kPa or below after
evacuating for 2 hours or more, repeat a vacuum breakdown
and vacuum drying.
8-5 Pipe insulation
• Insulation of pipes should be done after performing "AIR TIGHT
TEST AND VACUUM DRYING".
• Always insulate the liquid side piping and gas side piping in the
interunit piping and refrigerant branching kit. Failing to insulate
the pipes could cause leaking or burns. (The gas side piping can
reach temperatures of 120°C. Be sure the insulation used can
withstand such temperatures.)
• Reinforce the insulation on the refrigerant piping according to the
installation environment. Condensation might form on the surface
of the insulation.
Ambient temperature: 30°C, humidity: 75% to 80% RH: min.
thickness: 15 mm.
If the ambient temperature exceeds 30°C and the humidity
80% RH, then the min. thickness is 20 mm.
• If there is a possibility that condensation on the shutoff 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, etc., this must be prevented by caulking the connec-
tions, etc.
Liquid side
shutoff valve
Gas side
shutoff valve
Indoor interunit
piping
• The piping lead-out hole lid should be attached after opening a
knock hole.
If small animals and the like might enter the unit through the pip-
ing lead-out hole, close the hole with blocking material (procured
on site) after completion of "9. PROCEDURE OF ADDING
REFRIGERANT CHARGING AND CHECK OPERATION".
The piping outlet port is used to draw in the charge hose at the
time of work specified in "9. PROCEDURE OF ADDING REFRIG-
ERANT CHARGING AND CHECK OPERATION".
Piping lead-out
hole lid
Open a knock
hole at
Note
• After knocking out the holes, we recommend you remove burrs in
the knock holes and paint the edges and areas around the edges
using the repair paint.
Coking, etc.
Insulation material
Block
Liquid side piping
Gas side piping
English
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