—11—
— Replacement of the refrigeration cycle.
1. When replacing the refrigeration cycle, be sure to
discharge the refrigerant using a Freon
TM
recovery
System.
If there is no valve to attach the recovery system,
install one (such as a WATCO A-1) before venting the
Freon
TM
. Leave the valve in place after
servicing the system.
2. After discharging the unit completely, remove the
desired component, and unbraze the pinch-off tubes.
3. Solder service valves into the pinch-off tube ports,
leaving the valves open.
4. Solder the pinch-off tubes with Service valves.
5. Evacuate as follows.
1) Connect the vacuum pump, as illustrated figure
18A.
2) Start the vacuum pump, slowly open manifold
valves A and B with two full turns counterclockwise
and leave the valves open.
The vacuum pump is now pulling through valves A
and B by means of the manifold.
3) Operate the vacuum pump for 20 to 30 minutes,
until 600 microns of vaccum is obtained. Close
valves A and B, and observe vacuum gauge for
a few minutes. A rise in pressure would
indicate a possible leak or moisture remaining in
the system. With valves A and B closed, stop
the vacuum pump.
4) Remove the hose from the vacuum pump and
place it on the charging cylinder. See figure 18B.
Open valve C.
Discharge the line at the manifold connection.
5) The system is now ready for final charging.
6. Recharge as follows :
1) Refrigeration cycle systems are charged from the
High-side. If the total charge cannot be put
in the High-side, the balance will be put in the
suction line through the access valve which you
installed as the system was opened.
2) Connect the charging cylinder as shown in figure
18B.
With valve C open, discharge the hose at the
manifold connection.
3) Open valve A and allow the proper charge to
enter the system. Valve B is still closed.
4) If more charge is required, the high-side will not
take it. Close valve A.
5) With the unit running, open valve B and add the
balance of the charge.
a. Do not add the liquid refrigerant to the Low-side.
b. Watch the Low-side gauge; The pressure of
optimum condition is as below.(Cooling)
NOTE: If the actual pressure are higher than
shown, the system is most likely over-
charged, and charge should be removed.
If the actual pressure are lower than
shown, the system is most likely
undercharged, and charge should be
added.
c. Turn off valve B and allow pressure to drop.
d. Repeat steps b. and c. until the balance of the
charge is in the system.
6) When satisfied the unit is operating correctly,
use the pinch-off tool with the unit still running
and clamp on to the pinch-off tube. Using a tube
cutter, cut the pinch-off tube about 2 inches from
the pinch-off tool. Use sil-fos solder and sold
pinch-off tube closed. Turn off the unit, allow it to
set for a while, and then test the leakage of the
pinch-off connection.
NOTES
• Use vacuum pump equipped with check valve
applied to be prevented from flowing backward.
• If high vacuum equipment is used, open slowly
with the two full turns counterclockwise. This will
keep oil from foaming and being drawn into the
vacuum pump.
Do not use the existing charge set for R-22.
It is necessary to use new charge set for R-410A.
The pressure of R-410A is 1.6 times higher than
that of R-22. Thus, the high pressure side gauge of
charge set should be used higher pressure gauge
of 50kg/cm
2
range.
CAUTION
CAUTION
OUTSIDE TEMPERATURE THE PRESSURE OF LOW-SIDE GAUGE
35°C(95°F)
9.2~9.7 kgf/cm
2
.G
(130.9~138.0 lbf/in
2
.G)
