5
5. Refrigerant piping work
5.2.5. Check (Fig. 5-7)
• Compare
the
fl
ared work with a
fi
gure in right side hand.
• If
fl
are is noted to be defective, cut off the
fl
ared section and do
fl
aring work again.
a
Smooth all around
f
Scratch on
fl
ared plane
b
Inside is shining without any scratches
g
Cracked
c
Even length all around
h
Uneven
d
Too much
i
Bad examples
e
Tilted
• Apply a thin coat of refrigeration oil on the seat surface of pipe. (Fig. 5-8)
• For connection
fi
rst align the center, then tighten the
fi
rst 3 to 4 turns of
fl
are nut.
• Use tightening torque table below as a guideline for indoor unit side union joint
section, and tighten using two wrenches. Excessive tightening damages the
fl
are
section.
Copper pipe O.D.
(mm)
Flare nut O.D.
(mm)
Tightening torque
(N·m)
ø6.35
17
14 - 18
ø9.52
22
34 - 42
ø12.7
26
49 - 61
ø15.88
29
68 - 82
Warning:
When installing the unit, securely connect the refrigerant pipes before starting
the compressor.
Warning:
Be careful of
fl
ying
fl
are nut! (Internally pressurized)
Remove the
fl
are nut as follows:
1. Loosen the nut until you hear a hissing noise.
2. Do not remove the nut until the gas has been completely released (i.e., hiss-
ing noise stops).
3. Check that the gas has been completely released, and then remove the nut.
Fig. 5-7
Fig. 5-8
1
0
/
2
3
4
5
6
7
B
5.5. Purging procedures leak test
Connect the refrigerant pipes (both the liquid and gas pipes) between the indoor
and the outdoor units.
After refrigerant pipes are connected and evacuated, fully open all stop valves on
gas and liquid pipe sides.
Operating without fully opening lowers the performance and causes trouble.
Pipe length :
7 m maximum
No gas charge is needed.
Pipe length exceeding 7 m
Charge the prescribed
amount of gas.
Remove the service port cap of the stop valve on the side of the outdoor unit gas
pipe. (The stop valve will not work in its initial state fresh out of the factory (totally
closed with cap on).)
Connect the gage manifold valve and the vacuum pump to the service port of the
stop valve on the gas pipe side of the outdoor unit.
Check the vacuum with the gage manifold valve, then close the gage manifold
valve, and stop the vacuum pump.
Leave it as is for one or two minutes. Make sure the pointer of the gage mani-
fold valve remains in the same position. Con
fi
rm that the pressure gage show
-0.101 MPa (-760 mmHg).
PURGING PROCEDURES
Remove the gage manifold valve quickly from the service port of the stop valve.
Run the vacuum pump. (Vacuumize for more than 15 minutes.)
Tighten the cap to the service port to obtain the initial status.
Retighten the cap.
Leak test
*Open
*Close
Hexagonal wrench
Vacuum
pump
Handle
Low
Stop
valve
Window
Stop valve
Service port
*4 to 5 turns
Charge hose
(for R410A)
Charge hose
(for R410A)
Handle High
Gauge manifold
valve (for R410A)
Pressure gauge
(for R410A)
Compound pressure
gauge (for R410A)
(or the vacuum
pump with the
function to
prevent the back
fl
ow)
Adapter for
preventing the
back
fl
ow
Stop valve
-0.101 MPa
(-760 mmHg)
