Panasonic S-3650PU3E Technical Data & Service Manual page 85

● For the flare nuts at tubing connections, be sure to use the
flare nuts that were supplied with the unit, or else flare nuts
for R410A, R32 (type 2). The refrigerant tubing that is used
must be of the correct wall thickness as shown in the table
below.
Tightening torque
Tube diameter
(approximate)
14 – 18 N · m
ø6.35 (1/4")
{140 – 180 kgf · cm}
34 – 42 N · m
ø9.52 (3/8")
{340 – 420 kgf · cm}
49 – 55 N · m
ø12.7 (1/2")
{490 – 550 kgf · cm}
68 – 82 N · m
ø15.88 (5/8")
{680 – 820 kgf · cm}
Because the pressure is approximately 1.6 times higher
than conventional refrigerant R22 pressure, the use of
ordinary flare nuts (type 1) or thin-walled tubes may result
in tube rupture, injury, or asphyxiation caused by refrigerant
leakage.
● In order to prevent damage to the flare caused by over-
tightening of the flare nuts, use the table above as a guide
when tightening.
● When tightening the flare nut on the liquid tube, use an
adjustable wrench with a nominal handle length of 200 mm.
●
Insulating the Refrigerant Tubing
Tubing Insulation
Must ensure that pipe-work shall be protected from physical
damage.
● Thermal insulation must be applied to all units tubing,
including distribution joint (field supply).
* For gas tubing, the insulation material must be heat
resistant to 120°C or above. For other tubing, it must be
heat resistant to 80°C or above.
Insulation material thickness must be 10 mm or greater.
If the conditions inside the ceiling exceed DB 30°C and RH
70%, increase the thickness of the gas tubing insulation
material by 1 step.
Two tubes arranged together
Liquid tubing
Insulation
CAUTION
If the exterior of the outdoor unit valves has been finished
with a square duct covering, make sure you allow sufficient
space to access the valves and to allow the panels to be
attached and removed.
Additional Precautions For R32 Models.
Ensure to do the re-flaring of pipes before connecting to units to
avoid leaking.
To prevent the ingress of moisture into the joint which could have the
potential to freeze and then cause leakage, the joint must be sealed
with suitable silicone and insulation material. The joint should be sealed
on both liquid and gas side.
Insulation material and silicone sealant. Please ensure
there are no gaps where moisture can enter the joint.
Silicone Sealant must be neutral cure and ammonia free. Use of silicon
containing ammonia can lead to stress corrosion on the joint and cause
leakage.
Tube thickness
0.8 mm
0.8 mm
0.8 mm
1.0 mm
Gas tubing
1-11-1-1-9
Taping the flare nuts
Wind the white insulating tape around the flare nuts at the gas
tube connections. Then cover up the tubing connections with
the flare insulator, and fill the gap at the union with the supplied
black insulating tape.
Different-diameter-tube joint
Insulating tape
(supplied)
Unit side
Flare nut
Flare union
Insulation material
The material used for insulation must have good insulation
characteristics, be easy to use, be age resistant, and must not
easily absorb moisture.
CAUTION
After a tube has been insulated, never try to bend it into
a narrow curve because it can cause the tube to break or
crack.
Never grasp the drain or refrigerant connecting outlets
when moving the unit.
●
Taping the Tubes
(1) At this time, the refrigerant tubes (and electrical wiring
if local codes permit) should be taped together with
armoring tape in 1 bundle. To prevent condensation from
overflowing the drain pan, keep the drain hose separate
from the refrigerant tubing.
(2) Wrap the armoring tape from the bottom of the outdoor
unit to the top of the tubing where it enters the wall. As you
wrap the tubing, overlap half of each previous tape turn.
(3) Clamp the tubing bundle to the wall, using 1 clamp approx.
each meter.
Insulated tubes
NOT E
Do not wind the armoring tape too tightly since this will
decrease the heat insulation effect. Also ensure that the
condensation drain hose splits away from the bundle and drips
clear of the unit and the tubing.
1
Insulating tape
(supplied)
Tube insulator
(not supplied)
Heat resistant
120°C or above
Clamp
Drain hose