Precautions For Installation Using New Refrigerant - Panasonic U-72MF2U9 Service Manual

Precautions for Installation Using New Refrigerant

1. Care regarding tubing
1-1. Process tubing
Material: Use clean, dry, free of oil, refrigeration grade, seamless, phosphorous deoxidized copper tube rated for
l
R410A only. Wall thickness shall comply with the applicable legislation. The minimal wall thickness must be in
accordance with the table below.
Tubing size: Be sure to use the sizes indicated in the table below.
l
Use a tube cutter when cutting the tubing, and be sure to remove any flash. This also applies to distribution joints
l
(optional).
When bending tubing, use a bending radius that is 4 times the outer diameter of the tubing or larger.
l
Use sufficient care in handling the tubing. Seal the tubing ends with caps or tape to
prevent dirt, moisture, or other foreign substances from entering.
CAUTION
These substances can result in system malfunction.
Material: O
Outer diameter Wall thickness
1/4" (6.35) 0.025 (0.635)
3/8" (9.52) 0.030 (0.762)
1/2" (12.7) 0.035 (0.889)
5/8" (15.88) 0.040 (1.016)
3/4" (19.05) 0.042 (1.0668)
1-2. Prevent impurities including water, dust and oxide from entering the tubing. Impurities can cause R410A
refrigerant deterioration and compressor defects. Due to the features of the refrigerant and refrigerating machine
oil, the prevention of water and other impurities becomes more important than ever.
2. Be sure to recharge the refrigerant only in liquid form.
2-1. Since R410A is a non-azeotrope, recharging the refrigerant in gas form can lower performance and cause defects
in the unit.
2-2. Since refrigerant composition changes and performance decreases when gas leaks, collect the remaining
refrigerant and recharge the required total amount of new refrigerant after fixing the leak.
3. Different tools required
3-1. Tool specifications have been changed due to the characteristics of R410A.
Some tools for R22- and R407C-type refrigerant systems cannot be used.
R407C tools
New
Item compatible
tools?
with R410A?
Manifold gauge Yes
Charge hose Yes
Vacuum pump Yes
Leak detector Yes
Flaring oil Yes
* Using tools for R22 and R407C and new tools for R410A together can cause defects.
Material: O
Outer diameter Wall thickness
7/8" (22.22) 0.045 (1.143)
1-1/8" (28.58) 0.050 (1.27)
1-3/8" (34.92) 0.055 (1.397)
1-5/8" (41.28) 0.060 (1.524)
Unit: in. (mm)
Types of refrigerant, refrigerating machine oil, and
No
pressure gauge are different.
No To resist higher pressure, material must be changed.
Use a conventional vacuum pump if it is equipped with
Yes a check valve. If it has no check valve, purchase and
attach a vacuum pump adapter.
Leak detectors for CFC and HCFC that react to chlorine
No do not function because R410A contains no chlorine.
Leak detector for HFC134a can be used for R410A.
For systems that use R22, apply mineral oil (Suniso
oil) to the flare nuts on the tubing to prevent refrigerant
No
leakage. For machines that use R407C or R410A, apply
synthetic oil (ether oil) to the flare nuts.
Remarks
iii
Manifold gauge
Vacuum pump
Outlet
Inlet