Panasonic CU-B14DBE5, Service Manual, Page: 70 / 109

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d. R410A refrigerating machine oil
Conventionally, mineral oil or a synthetic oil such as alkylbenzene has been used for R22 refrigerating machine oil.
Because of the poor compatibility between R410A and conventional oils like mineral oil, however, there is a tendency for
the refrigerating machine oil to collect in the refrigerating cycle. For this reason, polyester and other synthetic oils which
have a high compatibility with R410A are used as refrigerating machine oil.
Because of the high hygroscopic property of synthetic oil, more care must be taken in its handling than was necessary with
conventional refrigerating machine oils. Also, these synthetic oils will degrade if mixed with mineral oil or alkylbenzene,
causing clogging in capillary tubes or compressor malfunction. Do not mix them under any circumstances.
11.1.2. Safety measures when installing/servicing refrigerant piping
Cause the gas pressure of R410A is approximately 1.6 times as high as that of R22, a mistake in installation or servicing could
result in a major accident. It is essential that you use R410A tools and materials, and that you observe the following precautions to
ensure safety.
1. Do not use any refrigerant other than R410A in ACs that have been used with R410A.
2. If any refrigerant gas leaks while you are working, ventilate the room. Toxic gas may be generated if refrigerant gas is
exposed to a direct flame.
3. When installing or transferring an AC, do not allow any air or substance other than R410A to mix into the refrigeration cycle. If
it does, the pressure in the refrigeration cycle can become abnormally high, possibly causing an explosion and/or injury.
4. After finishing the installation, check to make sure there is no refrigerant gas leaking.
5. When installing or transferring an AC, follow the instructions in the installation instructions carefully. Incorrect installation can
result in an abnormal refrigeration cycle or water leakage, electric shock, fire, etc.
6. Do not perform any alterations on the AC unit under any circumstances. Have all repair work done by a specialist. Incorrect
repairs can result in a water leakage, electric shock, fire, etc.
11.2. Tools for installing/servicing refrigerant piping
11.2.1. Necessary tools
In order to prevent an R410A AC from mistakenly being charged with any other refrigerant, the diameter of the 3-way valve service
port on the outdoor unit has been changed. Also, to increase its ability to withstand pressure, the opposing dimensions have been
changed for the refrigerant pipe flaring size and flare nut. Accordingly, when installing or servicing refrigerant piping, you must have
both the R410A and ordinary tools listed below.
Table 3 Tools for installation, transferring or replacement
*1) You can use the conventional (R22) flaring tool. If you need to buy a new tool, buy the R410A type.
*2) Use when it is necessary to detect small gas leaks.
For other installation work, you should have the usual tools, such as screwdrivers (+,-), a metal-cutting saw, an electrical drill, a hole
core drill (65 or 70 dia.), a tape measure, a level, a thermometer, a clamp meter, an insulation tester, a voltmeter, etc.
Table 4 Tools for serving
*1) Always replace the dryer of the outdoor unit at the same time. The replacement dryer is wrapped in a vacuum pack. Replace it
last among the refrigerating cycle parts. Start brazing as soon as you have opened the vacuum pack, and begin the vacuuming
operation within 2 hours.
Type of work Ordinary tools R410A tools
Flaring Flaring tool (clutch type), pipe cutter,
reamer Copper pipe gauge for clearance Adjust-
ment, flaring tool (clutch type)*1)
Bending, connecting pipes Torque wrench (nominal diameter 1/4, 3/
8,1/2). Fixed spanner (opposing sides 12
mm, 17 mm, 19 mm). Adjustable wrench,
Spring bender
Air purging Vacuum pump. Hexagonal wrench (oppos-
ing sides 4 mm) Manifold gauge, charging hose, vacuum
pump adaptor
Gas leak inspection Gas leak inspection fluid or soapy water Electric gas leak detector for HFC refriger-
ant*2)
Type of work Ordinary tools R410A tools
Refrigerant charging Electronic scale for refrigerant charging.
Refrigerant cylinder. Charging orifice and
packing for refrigerant cylinder
Brazing (Replacing refrigerating cycle
part*1) Nitrogen blow set (be sure to use nitrogen
blowing for all brazing), and brazing
machine