Panasonic U-72MF1U9 Installation Instructions Manual page 27

●
Tighten each cap as specified below.
Tightening torque for each cap
Service port cap
60 – 100 lbs · in (70 – 120 kgf · cm)
(width 19/32")
Valve cap
170 – 220 lbs · in (200 – 250 kgf · cm)
(width 55/64")
Flare nut
300 – 360 lbs · in (340 – 420 kgf · cm)
(valve dia. ø3/8")
Do not apply an adjustable wrench
to the hexagonal part.
Do not use two adjustable wrenches
when removing or installing the balance
tube flare nut. In particular, do not apply
an adjustable wrench to the hexagonal
part at the top of the valve.
(If force is applied to this part,
gas leakage will occur.)
● Precautions for brazing
Be sure to replace the air inside the tube with nitrogen to prevent oxide film from forming during the brazing process.
Be sure to use a damp cloth or other means to cool the valve unit during brazing.
Work method
Field-supply tube
Brazing locations
1. Be sure to use nitrogen. (Oxygen, CO
2. Use a pressure-reducing valve on the nitrogen tank.
CAUTION
3. Do not use agents intended to prevent the formation of oxide film. They will adversely affect the
refrigeration oil, and may cause equipment failure.
4. The balance tube is not used if only 1 outdoor unit is installed.
Use the unit in the same conditions as when it was shipped from the factory.
Flare nut
Use two adjustable wrenches, as shown in the figure,
when removing the liquid tube valve flare nut.
1. Do not apply a wrench to the valve cap when removing or
installing the flare nuts. Doing so may damage the valve.
2. If the valve cap is left off for a long period of time, refrigerant
leakage will occur. Therefore, do not leave the valve cap off.
3. Applying refrigerant oil to the flare surface can be effective in
preventing gas leakage, however be sure to use a refrigerant
oil which is suitable for the refrigerant that is used in the system.
(This unit utilizes R410A refrigerant, and the refrigerant oil is
ether oil (synthetic oil). However, hub oil (synthetic oil) can also
be used.)
Pressure-reducing valve (regulator)
Remote valve
Taping
, and CFC must not be used.)
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Valve cap
Service port cap