Panasonic U-26PE1U6, Technical Data & Service Manual

Page: 5 / 297

iii iv
Precautions for Installation Using New Refrigerant
1. Care regarding tubing
1-1. Process tubing
Material: Use C1220 phosphorous deoxidized copper specified in JIS H3300 “Copper and Copper Alloy Seamless
Pipes and Tubes.”
Tubing size: Be sure to use the sizes indicated in the table below.
Use a tube cutter when cutting the tubing, and be sure to remove any flash. This also applies to distribution joints
(optional).
When bending tubing ø5/8" or smaller, use a bending radius that is 4 times the outer diameter of the tubing or larger.
CAUTION
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. These substances can result in system malfunction.
O Material
Copper tube
Outer diameter 1/4 3/8 1/2 5/8
Wall thickness t0.032 t0.032 t0.032 t0.04
Unit: inch
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.
defects of the unit.
2-2.
Since R410A is a non-azeotrope, recharging the refrigerant in gas form can lower performance and cause
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.
Check of Density Limit
The room in which the air conditioner is to be
installed requires a design that in the event of refrig-
erant gas leaking out, its density will not exceed a set
limit.
The refrigerant (R410A), which is used in the air condition-
er, is safe, without the toxicity or combustibility of ammonia,
and is not restricted by laws imposed to protect the ozone
layer. However, since it contains more than air, it poses the
risk of suffocation if its density should rise excessively. Suf-
focation from leakage of refrigerant is almost non-existent.
With the recent increase in the number of high density
buildings, however, the installation of multi air conditioner
systems is on the increase because of the need for effec-
tive use of floor space, individual control, energy conserva-
tion by curtailing heat and carrying power, etc.
Most importantly, the multi air conditioner system is able
to replenish a large amount of refrigerant compared to
conventional individual air conditioners. If a single unit of
the multi air conditioner system is to be installed in a
small room, select a suitable model and installation pro-
cedure so that if the refrigerant accidentally leaks out, its
density does not reach the limit (and in the event of an
emergency, measures can be made before injury can
occur).
ASHRAE and the International Mechanical Code of the
ICC as well as CSA provide guidance and define safe-
guards related to the use of refrigerants, all of which define
a Refrigerant Concentration Level (RCL) of 25 pounds
per 1,000 cubic feet for R410A refrigerant.
For additional guidance and precautions related to
refrigerant safety, please refer to the following documents:
International Mechanical Code 2012 (IMC-2012)
(or more recently revised)
ASHRAE 15
ASHRAE 34
3-2. Use R410A exclusive cylinder only.
When charging with a refrigerant cylinder, use an electronic scale for charging refrigerant.
In this case, if the volume of refrigerant in the cylinder becomes less than 20% of the fully-charged amount, the
composition of the refrigerant starts to change.
Thus, do not use the refrigerant if the amount in the charging cylinder is less than 20%.
Also, charge the minimum necessary amount to the charging cylinder before using it to charge the air conditioning unit.
Configuration and characteristics of cylinders
Single valve
Charge liquid refrigerant with
cylinder in up-side-down position.
Fig. 1
Valve
Liquid
Single valve (with siphon tube)
Charge with cylinder in normal position.
Fig. 2
Valve
Liquid
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.
Item
New
tool?
R407C tools
compatible
with R410A?
Remarks
Manifold gauge
Yes
No
No
No
No
Yes
Yes
Yes
Yes
Yes
Types of refrigerant, refrigerating machine oil, and
pressure gauge are different.
To resist higher pressure, material must be changed.
Charge hose
Use a conventional vacuum pump if it is equipped
with a check valve. If it has no check valve,
purchase and attach a vacuum pump adapter.
Vacuum pump
Leak detectors for CFC and HCFC that
react to chlorine do not function because
R410A contains no chlorine. Leak detector
for HFC134a can be used for R410A.
Leak detector
For systems that use R22, apply mineral oil (Suniso oil)
to the flare nuts on the tubing to prevent refrigerant
leakage. For machines that use R407C or R410A, apply
synthetic oil (ether oil) to the flare nuts.
Flaring oil
* Using tools for R22 and R407C and new tools for R410A together can cause defects.
Manifold gauge
Vacuum pump
Outlet
Inlet
SM830203-04.indb 5 15/10/13 17:18:01